<PAGE>
                                                                   EXHIBIT 10.21

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED.  THE SECURITIES HAVE BEEN ACQUIRED FOR
INVESTMENT AND MAY NOT BE RESOLD, TRANSFERRED OR ASSIGNED IN THE ABSENCE OF AN
EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT OF
1933, AS AMENDED, OR AN OPINION OF COUNSEL THAT REGISTRATION IS NOT REQUIRED
UNDER SAID ACT.

                                     Right to Purchase 333,116 Shares of Common
                                     Stock of Equalnet Communications Corp.


                         EQUALNET COMMUNICATIONS CORP.

                         COMMON STOCK PURCHASE WARRANT
NO. W-1

          EQUALNET COMMUNICATIONS CORP., a Texas corporation (the "Company"),
hereby certifies that, for value received, Genesee Fund Limited-Portfolio B or
registered assigns (the "Holder"), is entitled, subject to the terms set forth
below, to purchase from the Company at any time or from time to time after the
date hereof, and before 5:00 p.m., New York City time, on the Expiration Date
(as defined herein), 333,116 fully paid and nonassessable shares of Common Stock
(as defined herein) at a purchase price per share equal to the Purchase Price
(as hereinafter defined).  The number of such shares of Common Stock and the
Purchase Price are subject to adjustment as provided in this Warrant.

          As used herein the following terms, unless the context otherwise
requires, have the following respective meanings:

          "AMEX" means the American Stock Exchange, Inc.

          "Common Stock" includes the Company's Common Stock, $.01 par value per
share, as authorized on the date hereof, and any other securities into which or
for which the Common Stock may be converted or exchanged pursuant to a plan of
recapitalization, reorganization, merger, sale of assets or otherwise.

          "Company" shall include Equalnet Communications Corp. and any
corporation that shall succeed to or assume the obligation of Equalnet
Communications Corp. hereunder in accordance with the terms hereof.

          "Expiration Date" means September 4, 2003.

          "Issuance Date" means the first date of original issuance of this
Warrant.
<PAGE>
 
          "Maximum Share Amount" shall have the meaning provided in the
Note.     
          
          "Nasdaq" means the Nasdaq National Market.
          
          "Nasdaq SmallCap" means the Nasdaq SmallCap Market.
          
          "1934 Act" means the Securities Exchange Act of 1934, as amended.
          
          "1933 Act" means the Securities Act of 1933, as amended.

          "Note" means the 6% Senior Secured Convertible Note due 2001 issued by
the Company, all 6% Senior Secured Convertible Notes due 2001 issued by the
Company upon transfer, re-registration or split-up thereof and all Interest
Notes, as defined therein.

          "Note Purchase Agreement" means the Note Purchase Agreement or the
Note Purchase and Exchange Agreement, as the case may be, dated as of July 31
1998, by and between the Company and the original Holder of this Warrant, as
amended from time to time in accordance with its terms.

          "NYSE" shall mean the New York Stock Exchange, Inc.

          "Other Securities" refers to any stock (other than Common Stock) and
other securities of the Company or any other person (corporate or otherwise)
which the Holder at any time shall be entitled to receive, or shall have
received, on the exercise of this Warrant, in lieu of or in addition to Common
Stock, or which at any time shall be issuable or shall have been issued in
exchange for or in replacement of Common Stock or Other Securities pursuant to
Section 4.

          "Purchase Price" shall mean $.9006 per share, subject to adjustment as
provided in this Warrant.

          "Registration Rights Agreement" means the Registration Rights
Agreement, dated as of July 31, 1998, by and between the Company and the
original Holder of this Warrant, as amended from time to time in accordance with
its terms.

          "Stockholder Approval" means the approval by a majority of the votes
cast by the holders of shares of Common Stock (in person or by proxy) at a
meeting of the stockholders of the Company (duly convened at which a quorum was
present), or a written consent of holders of shares of Common Stock entitled to
such number of votes given without a meeting, of the issuance by the Company of
20% or more of the outstanding Common Stock of the Company for less than the
greater of the book or market value of such Common Stock on conversion of this
Note and the Other Notes, as and to the extent required under Rule 4460(i) of
Nasdaq as in effect at such time (or any successor or replacement provision
thereof).

                                      -2-
<PAGE>
 
          "Trading Day" means a day on which the principal securities market for
the Common Stock is open for general trading of securities.

          1.   EXERCISE OF WARRANT.

          1.1  EXERCISE.  (a) This Warrant may be exercised by the Holder
hereof in full or in part at any time or from time to time during the exercise
period specified in the first paragraph hereof until the Expiration Date by
surrender of this Warrant and the subscription form annexed hereto (duly
executed by the Holder), to the Company's transfer agent and registrar for the
Common Stock, and by making payment, in cash or by certified or official bank
check payable to the order of the Company, in the amount obtained by multiplying
(a) the number of shares of Common Stock designated by the Holder in the
subscription form by (b) the Purchase Price then in effect.  On any partial
exercise the Company will forthwith issue and deliver to or upon the order of
the Holder hereof a new Warrant or Warrants of like tenor, in the name of the
Holder hereof or as the Holder (upon payment by the Holder of any applicable
transfer taxes) may request, providing in the aggregate on the face or faces
thereof for the purchase of the number of shares of Common Stock for which such
Warrant or Warrants may still be exercised.

          (b) Notwithstanding any other provision of this Warrant, in no event
shall the Holder be entitled at any time to purchase a number of shares of
Common Stock on exercise of this Warrant in excess of that number of shares upon
purchase of which the sum of (1) the number of shares of Common Stock
beneficially owned by the Holder and all persons whose beneficial ownership of
shares of Common Stock would be aggregated with the Holder's beneficial
ownership of shares of Common Stock for purposes of Section 13(d) of the 1934
Act and Regulation 13D-G thereunder, (each such person other than the Holder an
"Aggregated Person" and all such persons other than the Holder, collectively,
the "Aggregated Persons") (other than shares of Common Stock deemed beneficially
owned through the ownership by the Holder and all Aggregated Persons of the
Holder of the unexercised portion of this Warrant and any other security of the
Company which contains similar provisions) and (2) the number of shares of
Common Stock issuable upon exercise of the portion of this Warrant with respect
to which the determination in this sentence is being made, would result in
beneficial ownership by the Holder and all Aggregated Persons of the Holder of
more than 4.9% of the outstanding shares of Common Stock. For purposes of the
immediately preceding sentence, beneficial ownership shall be determined in
accordance with Section 13(d) of the 1934 Act and Regulation 13D-G thereunder,
except as otherwise provided in clause (1) of the immediately preceding
sentence. For purposes of the second preceding sentence, the Company shall be
entitled to rely, and shall be fully protected in relying, on any statement or
representation made by the Holder to the Company in connection with a particular
exercise of this Warrant, without any obligation on the part of the Company to
make any inquiry or investigation or to examine its records or the records of
any transfer agent for the Common Stock.

          1.2  NET ISSUANCE. Notwithstanding anything to the contrary contained
in Section 1.1, the Holder may elect to exercise this Warrant in whole or in
part by receiving shares of Common Stock equal to the net issuance value (as
determined below) of this Warrant, or any

                                      -3-
<PAGE>
 
part hereof, upon surrender of this Warrant to the Company's transfer agent and
registrar for the Common Stock the principal office of the Company together with
the subscription form annexed hereto (duly executed by the Holder), in which
event the Company shall issue to the Holder a number of shares of Common Stock
computed using the following formula:

               X = Y (A-B)
                   -------
                     A

        Where: X =  the number of shares of Common Stock to be issued
                    to the Holder

               Y =  the number of shares of Common Stock as to which
                    this Warrant is to be exercised

               A =  the current fair market value of one share of
                    Common Stock calculated as of the last trading day
                    immediately preceding the exercise of this Warrant

               B =  the Purchase Price

          As used herein, current fair market value of Common Stock as of a
specified date shall mean with respect to each share of Common Stock the average
of the closing sale price of the Common Stock on the principal securities market
on which the Common Stock may at the time be listed or, if there have been no
sales on any such exchange on such day, the average of the highest bid and
lowest asked prices on the principal securities market at the end of such day,
or, if on such day the Common Stock is not so listed, the average of the
representative bid and asked prices quoted in the Nasdaq System as of 4:00 p.m.,
New York City time, or, if on such day the Common Stock is not quoted in the
Nasdaq System, the average of the highest bid and lowest asked price on such day
in the domestic over-the-counter market as reported by the National Quotation
Bureau, Incorporated, or any similar successor organization, in each such case
averaged over a period of five consecutive Trading Days consisting of the day as
of which the current fair market value of a share of Common Stock is being
determined (or if such day is not a Trading Day, the Trading Day next preceding
such day) and the four consecutive Trading Days prior to such day. If on the
date for which current fair market value is to be determined the Common Stock is
not listed on any securities exchange or quoted in the Nasdaq System or the
over-the-counter market, the current fair market value of Common Stock shall be
the highest price per share which the Company could then obtain from a willing
buyer (not a current employee or director) for shares of Common Stock sold by
the Company, from authorized but unissued shares, as determined in good faith by
the Board of Directors of the Company, unless prior to such date the Company has
become subject to a merger, acquisition or other consolidation pursuant to which
the Company is not the surviving party, in which case the current fair market
value of the Common Stock shall be deemed to be the value received by the
holders of the Company's Common Stock for each share thereof pursuant to the
Company's acquisition.

                                      -4-
<PAGE>
 
          1.3       LIMITATION ON SHARES ISSUABLE ON EXERCISE.  Notwithstanding
any other provision herein, unless the Stockholder Approval shall have been
obtained from the stockholders of the Company or waived by the Nasdaq (or other
appropriate stock exchange or market), so long as the Common Stock is listed on
the Nasdaq, the Nasdaq SmallCap, the NYSE or the AMEX the Company shall not be
required to issue upon conversion of this Warrant a number of shares of Common
Stock in excess of the Maximum Share Amount.  The Company shall maintain records
which show the number of shares of Common Stock issued by the Company upon
conversion from time to time of the Note and exercise of this Warrant, which
records shall be controlling in the absence of manifest error.  Upon surrender
of this Warrant for transfer or re-registration hereof (or, at the option of the
Holder, for exercise of less than all of this Warrant), the Company shall make a
notation on the new Warrant issued upon such transfer or re-registration or
evidencing such unexercised portion of this Warrant, as the case may be, as to
the remaining number of shares of Common Stock from the Maximum Share Amount
remaining available for conversion of the Note and exercise of the Warrant
evidenced by such new certificate.  If this Warrant is surrendered for split-up
into two or more Warrants representing the right to purchase an aggregate number
of shares equal to the number of shares which may be purchased upon exercise of
this Warrant at the time so surrendered (as reduced by any contemporaneous
exercise of this Warrant), each Warrant issued on such split-up shall bear a
notation of the portion of the Maximum Share Amount allocated thereto determined
by pro rata allocation from among the remaining Maximum Share Amount at the time
this Warrant is so surrendered.

          2.        DELIVERY OF STOCK CERTIFICATES, ETC., ON EXERCISE.  As soon
as practicable after the exercise of this Warrant, and in any event within three
Trading Days thereafter, the Company at its expense (including the payment by it
of any applicable issue or stamp taxes) will cause to be issued in the name of
and delivered to the Holder hereof, or as the Holder (upon payment by the Holder
of any applicable transfer taxes) may direct, a certificate or certificates for
the number of fully paid and nonassessable shares of Common Stock (or Other
Securities) to which the Holder shall be entitled on such exercise, in such
denominations as may be requested by the Holder, plus, in lieu of any fractional
share to which the Holder would otherwise be entitled, cash equal to such
fraction multiplied by the then current fair market value (as determined in
accordance with subsection 1.2) of one full share, together with any other stock
or other securities any property (including cash, where applicable) to which the
Holder is entitled upon such exercise pursuant to Section 1 or otherwise.  Upon
exercise of this Warrant as provided herein, the Company's obligation to issue
and deliver the certificates for Common Stock shall be absolute and
unconditional, irrespective of the absence of any action by the Holder to
enforce the same, any waiver or consent with respect to any provision thereof,
the recovery of any judgment against any person or any action to enforce the
same, any failure or delay in the enforcement of any other obligation of the
Company to the Holder, or any setoff, counterclaim, recoupment, limitation or
termination, or any breach or alleged breach by the Holder or any other person
of any obligation to the Company, and irrespective of any other circumstance
which might otherwise limit such obligation of the Company to the Holder in
connection with such exercise.  If the Company fails to issue and deliver the
certificates for the Common Stock to the Holder pursuant to the first sentence
of this paragraph as and when required to do so, in addition to any other
liabilities the Company may have hereunder and under applicable law, the Company

                                      -5-
<PAGE>
 
shall pay or reimburse the Holder on demand for all out-of-pocket expenses
including, without limitation, fees and expenses of legal counsel incurred by
the Holder as a result of such failure.

               3. ADJUSTMENT FOR DIVIDENDS IN OTHER STOCK, PROPERTY, ETC.;
RECLASSIFICATION, ETC.  In case at any time or from time to time, all the
holders of Common Stock (or Other Securities) shall have received, or (on or
after the record date fixed for the determination of stockholders eligible to
receive) shall have become entitled to receive, without payment therefor,

               (a) other or additional stock or other securities or property
(other than cash) by way of dividend, or

               (b) any cash (excluding cash dividends payable solely out of
earnings or earned surplus of the Company), or

               (c) other or additional stock or other securities or property
(including cash) by way of spin-off, split-up, reclassification,
recapitalization, combination of shares or similar corporate rearrangement,

other than additional shares of Common Stock (or Other Securities) issued as a
stock dividend or in a stock-split (adjustments in respect of which are provided
for in Section 5), then and in each such case the Holder, on the exercise hereof
as provided in Section 1, shall be entitled to receive the amount of stock and
other securities and property (including cash in the cases referred to in
subdivisions (b) and (c) of this Section 3) which the Holder would hold on the
date of such exercise if on the date thereof the Holder had been the holder of
record of the number of shares of Common Stock called for on the face of this
Warrant and had thereafter, during the period from the date hereof to and
including the date of such exercise, retained such shares and all such other or
additional stock and other securities and property (including cash in the case
referred to in subdivisions (b) and (c) of this Section 3) receivable by the
Holder as aforesaid during such period, giving effect to all adjustments called
for during such period by Section 4.

               4. EXERCISE UPON REORGANIZATION, CONSOLIDATION, MERGER, ETC.
In case at any time or from time to time, the Company shall (a) effect a
reorganization, (b) consolidate with or merge into any other person, or (c)
transfer all or substantially all of its properties or assets to any other
person under any plan or arrangement contemplating the dissolution of the
Company, then, in each such case, as a condition of such reorganization,
consolidation, merger, sale or conveyance, the Company shall give at least 30
days notice to the Holder of such pending transaction whereby the Holder shall
have the right to exercise this Warrant prior to any such reorganization,
consolidation, merger, sale or conveyance.  Any exercise of this Warrant
pursuant to notice under this Section shall be conditioned upon the closing of
such reorganization, consolidation, merger, sale or conveyance which is the
subject of the notice and the exercise of this Warrant shall not be deemed to
have occurred until immediately prior to the closing of such transaction.

                                      -6-
<PAGE>
 
               5. ADJUSTMENT FOR EXTRAORDINARY EVENTS.  In the event that the
Company shall (i) issue additional shares of the Common Stock as a dividend or
other distribution on outstanding Common Stock, (ii) subdivide or reclassify its
outstanding shares of Common Stock, or (iii) combine its outstanding shares of
Common Stock into a smaller number of shares of Common Stock, then, in each such
event, the Purchase Price shall, simultaneously with the happening of such
event, be adjusted by multiplying the Purchase Price in effect immediately prior
to such event by a fraction, the numerator of which shall be the number of
shares of Common Stock outstanding immediately prior to such event and the
denominator of which shall be the number of shares of Common Stock outstanding
immediately after such event, and the product so obtained shall thereafter be
the Purchase Price then in effect.  The Purchase Price, as so adjusted, shall be
readjusted in the same manner upon the happening of any successive event or
events described herein in this Section 5.  The Holder shall thereafter, on the
exercise hereof as provided in Section 1, be entitled to receive that number of
shares of Common Stock determined by multiplying the number of shares of Common
Stock which would be issuable on such exercise immediately prior to such
issuance by a fraction of which (i) the numerator is the Purchase Price in
effect immediately prior to such issuance and (ii) the denominator is the
Purchase Price in effect on the date of such exercise.

               6. FURTHER ASSURANCES.  The Company will take all action that
may be necessary or appropriate in order that the Company may validly and
legally issue fully paid and nonassessable shares of stock, free from all taxes,
liens and charges with respect to the issue thereof, on the exercise of all or
any portion of this Warrant from time to time outstanding.

               7. NOTICES OF RECORD DATE, ETC.  In the event of

          (a) any taking by the Company of a record of the holders of any class
  of securities for the purpose of determining the holders thereof who are
  entitled to receive any dividend on, or any right to subscribe for, purchase
  or otherwise acquire any shares of stock of any class or any other securities
  or property, or to receive any other right, or

          (b) any capital reorganization of the Company, any reclassification or
  recapitalization of the capital stock of the Company or any transfer of all or
  substantially all of the assets of the Company to or consolidation or merger
  of the Company with or into any other person, or

          (c) any voluntary or involuntary dissolution, liquidation or
  winding-up of the Company,

then and in each such event the Company will mail or cause to be mailed to the
Holder, at least ten days prior to such record date, a notice specifying (i) the
date on which any such record is to be taken for the purpose of such dividend,
distribution or right, and stating the amount and character of such dividend,
distribution or right, (ii) the date on which any such reorganization,
reclassification, recapitalization, transfer, consolidation, merger,
dissolution, liquidation or winding-up is to take place, and the time, if any is
to be fixed, as of which the holders of record of Common Stock (or Other
Securities) shall be entitled to exchange their shares of Common

                                      -7-
<PAGE>
 
Stock (or Other Securities) for securities or other property deliverable on such
reorganization, reclassification, recapitalization, transfer, consolidation,
merger, dissolution, liquidation or winding-up, and (iii) the amount and
character of any stock or other securities, or rights or options with respect
thereto, proposed to be issued or granted, the date of such proposed issue or
grant and the persons or class of persons to whom such proposed issue or grant
is to be offered or made. Such notice shall also state that the action in
question or the record date is subject to the effectiveness of a registration
statement under the 1933 Act, or a favorable vote of stockholders if either is
required. Such notice shall be mailed at least ten days prior to the date
specified in such notice on which any such action is to be taken or the record
date, whichever is earlier.

          8. RESERVATION OF STOCK, ETC., ISSUABLE ON EXERCISE OF
WARRANTS.  The Company will at all times reserve and keep available out of its
authorized but unissued shares of capital stock, solely for issuance and
delivery on the exercise of this Warrant, a sufficient number of shares of
Common Stock (or Other Securities) to effect the full exercise of this Warrant
and the exercise, conversion or exchange of any other warrant or security of the
Company exercisable for, convertible into, exchangeable for or otherwise
entitling the holder to acquire shares of Common Stock (or Other Securities),
and if at any time the number of authorized but unissued shares of Common Stock
(or Other Securities) shall not be sufficient to effect such exercise,
conversion or exchange, the Company shall take such action as may be necessary
to increase its authorized but unissued shares of Common Stock (or Other
Securities) to such number as shall be sufficient for such purposes.

          9. TRANSFER OF WARRANT.  This Warrant shall inure to the
benefit of the successors to and assigns of the Holder.  This Warrant and all
rights hereunder, in whole or in part, are registrable at the office or agency
of the Company referred to below by the Holder hereof in person or by his duly
authorized attorney, upon surrender of this Warrant properly endorsed.

          10. REGISTER OF WARRANTS.  The Company shall maintain, at the
principal office of the Company (or such other office as it may designate by
notice to the Holder hereof), a register in which the Company shall record the
name and address of the person in whose name this Warrant has been issued, as
well as the name and address of each successor and prior owner of such Warrant.
The Company shall be entitled to treat the person in whose name this Warrant is
so registered as the sole and absolute owner of this Warrant for all purposes.

          11. EXCHANGE OF WARRANT.  This Warrant is exchangeable, upon the
surrender hereof by the Holder hereof at the office or agency of the Company
referred to in Section 10, for one or more new Warrants of like tenor
representing in the aggregate the right to subscribe for and purchase the number
of shares of Common Stock which may be subscribed for and purchased hereunder,
each of such new Warrants to represent the right to subscribe for and purchase
such number of shares as shall be designated by said Holder hereof at the time
of such surrender.

          12. REPLACEMENT OF WARRANT.  On receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of any

                                      -8-
<PAGE>
 
such loss, theft or destruction of this Warrant, on delivery of an indemnity
agreement or security reasonably satisfactory in form and amount to the Company
or, in the case of any such mutilation, on surrender and cancellation of this
Warrant, the Company at its expense will execute and deliver, in lieu thereof, a
new Warrant of like tenor.

          13. WARRANT AGENT.  In accordance with the Transfer Agent
Instruction, dated September __, 1998, by and among the Company, American Stock
Transfer & Trust Company, as Transfer Agent and Registrar (the "Transfer
Agent"), and the original Holder of this Warrant and the other common stock
purchase warrants of like tenor issued by the Company in connection with the
issuance of this Warrant the Company has appointed the Transfer Agent as the
exercise agent for purposes of issuing shares of Common Stock (or Other
Securities) on the exercise of this Warrant pursuant to Section 1.  The Company
may, by notice to the Holder, appoint an agent having an office in the United
States of America for the purpose of exchanging this Warrant pursuant to Section
11 and replacing this Warrant pursuant to Section 12, or either of the
foregoing, and thereafter any such exchange or replacement, as the case may be,
shall be made at such office by such agent.

          14. REMEDIES.  The Company stipulates that the remedies at law of the
Holder in the event of any default or threatened default by the Company in the
performance of or compliance with any of the terms of this Warrant are not and
will not be adequate, and that such terms may be specifically enforced by a
decree for the specific performance of any agreement contained herein or by an
injunction against a violation of any of the terms hereof or otherwise.

          15. NO RIGHTS OR LIABILITIES AS A STOCKHOLDER.  This Warrant
shall not entitle the Holder hereof to any voting rights or other rights as a
stockholder of the Company.  No provision of this Warrant, in the absence of
affirmative action by the Holder hereof to purchase Common Stock, and no mere
enumeration herein of the rights or privileges of the Holder hereof, shall give
rise to any liability of the Holder for the Purchase Price or as a stockholder
of the Company, whether such liability is asserted by the Company or by
creditors of the Company.

          16. NOTICES, ETC.  All notices and other communications from the
Company to the registered Holder shall be mailed by first class certified mail,
postage prepaid, at such address as may have been furnished to the Company in
writing by the Holder or at the address shown for the Holder on the register of
Warrants referred to in Section 10.

          17. TRANSFER RESTRICTIONS.  By acceptance of this Warrant, the
Holder represents to the Company that this Warrant is being acquired for the
Holder's own account and for the purpose of investment and not with a view to,
or for sale in connection with, the distribution thereof, nor with any present
intention of distributing or selling the Warrant or the Common Stock issuable
upon exercise of the Warrant.  The Holder acknowledges and agrees that this
Warrant and, except as otherwise provided in the Registration Rights Agreement,
the Common Stock issuable upon exercise of this Warrant (if any) have not been
(and at the time of acquisition by the Holder, will not have been or will not
be), registered under the 1933 Act or under the securities laws of any state, in
reliance upon certain exemptive provisions of such statutes.  The Holder further
recognizes and acknowledges that because this Warrant and, except

                                      -9-
<PAGE>
 
as provided in the Registration Rights Agreement, the Common Stock issuable upon
exercise of this Warrant (if any) are unregistered, they may not be eligible for
resale, and may only be resold in the future pursuant to an effective
registration statement under the 1933 Act and any applicable state securities
laws, or pursuant to a valid exemption from such registration requirements.
Unless the shares of Common Stock issuable upon exercise of this Warrant have
theretofore been registered for resale under the 1933 Act, the Company may
require, as a condition to the issuance of Common Stock upon the exercise of
this Warrant (i) in the case of an exercise in accordance with Section 1.1
hereof, a confirmation as of the date of exercise of the Holder's
representations pursuant to this Section 17, or (ii) in the case of an exercise
in accordance with Section 1.2 hereof, an opinion of counsel reasonably
satisfactory to the Company that the shares of Common Stock to be issued upon
such exercise may be issued without registration under the 1933 Act.

          18. LEGEND.  Unless theretofore registered for resale under the
1933 Act, each certificate for shares issued upon exercise of this Warrant shall
bear the following legend:

  The securities represented by this certificate have not been registered under
  the Securities Act of 1933, as amended. The securities have been acquired for
  investment and may not be resold, transferred or assigned in the absence of an
  effective registration statement for the securities under the Securities Act
  of 1933, as amended, or an opinion of counsel that registration is not
  required under said Act.

          19. MISCELLANEOUS.  This Warrant and any terms hereof may be
changed, waived, discharged or terminated only by an instrument in writing
signed by the party against which enforcement of such change, waiver, discharge
or termination is sought.  This Warrant shall be construed and enforced in
accordance with and governed by the internal laws of the State of New York.  The
headings in this Warrant are for purposes of reference only, and shall not limit
or otherwise affect any of the terms hereof.  The invalidity or unenforceability
of any provision hereof shall in no way affect the validity or enforceability of
any other provision.

                                      -10-
<PAGE>
 
          IN WITNESS WHEREOF, the Company has caused this Warrant to be executed
on its behalf by one of its officers thereunto duly authorized.

Dated:  September 4, 1998                  EQUALNET COMMUNICATIONS CORP.



                                           By:    ____________________________

                                           Title: ____________________________

                                      -11-
<PAGE>
 
                             FORM OF SUBSCRIPTION

                         EQUALNET COMMUNICATIONS CORP.

                  (To be signed only on exercise of Warrant)

TO: American Stock Transfer & Trust Company,
     as Transfer Agent
    6201 Fifteenth Avenue
    Brooklyn, New York 11219

          1.   The undersigned Holder of the attached original, executed Warrant
hereby elects to exercise its purchase right under such Warrant with respect to
______________ shares of Common Stock, as defined in the Warrant, of Equalnet
Communications Corp., a Texas corporation (the "Company").

          2.   The undersigned Holder (check one):

    [ ]   (a)  elects to pay the aggregate purchase price for such shares
               of Common Stock (the "Exercise Shares") (i) by lawful money of
               the United States or the enclosed certified or official bank
               check payable in United States dollars to the order of the
               Company in the amount of $___________, or (ii) by wire transfer
               of United States funds to the account of the Company in the
               amount of $____________, which transfer has been made before or
               simultaneously with the delivery of this Form of Subscription
               pursuant to the instructions of the Company;

          or

    [ ]   (b)  elects to receive shares of Common Stock having a value
               equal to the value of the Warrant calculated in accordance with
               Section 1.2 of the Warrant.

          3.   Please issue a stock certificate or certificates representing the
appropriate number of shares of Common Stock in the name of the undersigned or
in such other names as is specified below:

          4.   The undersigned Holder hereby represents to the Company that the
exercise of the Warrant elected hereby does not violate Section 1.1(b) of the
Warrant.



                                         Name:    ___________________________

                                         Address: ___________________________

 

                                      -12-
<PAGE>
 
Dated: ____________ ___, _____          __________________________________
                                        (Signature must conform to name of
                                         Holder as specified on the face of
                                         the Warrant)

                                      -13-