<PAGE>
                                                                   EXHIBIT 10.21

                            INPLAY TECHNOLOGIES, INC.
                              COMMON STOCK WARRANT

THE SECURITIES REPRESENTED BY THIS CERTIFICATE MAY NOT BE OFFERED FOR SALE, SOLD
OR OTHERWISE DISPOSED OF EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
FILED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR PURSUANT TO AN EXEMPTION
FROM REGISTRATION UNDER SUCH ACT.

     This certifies that, for good and valuable consideration, receipt of which
is hereby acknowledged, ______________________ ("Holder") is entitled to
purchase, subject to the terms and conditions of this Warrant, from InPlay
Technologies, Inc., a Nevada corporation (the "Company"), _______________ fully
paid and nonassessable shares of the Company's common stock, $0.001 par value
per share ("Common Stock") of the Company, in accordance with Section 2 hereof,
during the period commencing on December 27, 2005 (the "Commencement Date") and
ending at 5:00 p.m. California time, on December 27, 2010 (the "Expiration
Date"), at which time this Warrant will expire and become void unless earlier
exercised or terminated as provided herein, including, without limitation,
pursuant to Section 3 below.

     This Warrant is being issued to the Holder in connection with the closing
of the transactions contemplated by that certain Securities Purchase Agreement,
dated as of December 27, 2005, by and among the Company and the Investors named
therein (the "Purchase Agreement"). Capitalized terms used herein and not
otherwise defined shall have the meanings given them in the Purchase Agreement.

     1. Exercise Price. The initial purchase price for the Shares shall be $3.44
per share. Such price shall be subject to adjustment pursuant to the terms
hereof (such price, as adjusted from time to time, is hereinafter referred to as
the "Exercise Price").

     2. Exercise and Payment. At any time after the Commencement Date, this
Warrant may be exercised, in whole or in part, from time to time by the Holder,
during the term hereof, by surrender of this Warrant and the notice of exercise
annexed hereto (the "Notice of Exercise") duly completed and executed by the
Holder to the Company at the principal executive offices of the Company,
together with payment of an amount equal to the Exercise Price then in effect
multiplied by the number of Shares thereby purchased, as designated in the
Notice of Exercise. Payment of such aggregate Exercise Price may be made by the
Holder in cash, by check payable to the order of the Company or by wire transfer
of immediately available funds to an account designated by the Company.

     3. Call of Warrant. In the event the Closing Price of the Common Stock on
the Trading Market equals or exceeds $5.50 per share (as adjusted for any stock
split, stock dividend,


                                       1

<PAGE>

combination, recapitalization or similar event) for a period of 60 consecutive
Trading Days, then, following the end of such period, the Company may deliver to
each Holder, at the last address appearing on the records of the Company, a
written notice, in accordance with Section 18(b) below and containing the
information specified below (the "Call Notice"), requiring each such Holder to
exercise such Holder's Warrant in the manner provided in Section 2 above by no
later than 5:00 P.M. (Arizona time) on the tenth full Business Day following
each such Holder's receipt of such Call Notice (the "Redemption Date") Any such
Call Notice delivered in the manner provided herein and in Section 18(b) below
shall be conclusively presumed to have been given whether or not the Holder
actually receives such notice. In the event a Holder fails to exercise its
Warrant in the manner provided in Section 2 above prior to 5:00 P.M. (Arizona
time) on the Redemption Date, such Warrant shall automatically be deemed
canceled, terminated and of no further force or effect, and the Company shall
have no further obligations under this Warrant other than the obligation to pay
to such Holder an amount equal to $0.01 (the "Redemption Price") upon surrender
of the Warrant. For purposes of this Section 3, the following terms shall have
the following meanings:

          (a) "Business Day" means any day except Saturday, Sunday and any day
which is a federal legal holiday or a day on which banking institutions in the
State of New York are authorized or required by law or other governmental action
to close.

          (b) "Closing Price" means the closing price per share of the Common
Stock on the applicable Trading Market for a Trading Day.

          (c) "Trading Day" means (i) a day on which the Common Stock is traded
on a Trading Market, or (ii) if the Common Stock is not quoted on any Trading
Market, a day on which the Common Stock is quoted in the over-the-counter market
as reported by the Pink Sheets, LLC (or any similar organization or agency
succeeding to its functions of reporting prices).

          (d) "Trading Market" means whichever of the New York Stock Exchange,
the American Stock Exchange, the NASDAQ National Market, the NASDAQ SmallCap
Market or OTC Bulletin Board on which the Common Stock is listed or quoted for
trading on the date in question.

     The Call Notice shall specify (i) the Redemption Price, (ii) the Redemption
Date, (iii) the place where the Warrants shall be delivered, and (iv) that the
right to exercise the Warrant will terminate at 5:00 P.M. (Arizona time) on the
Redemption Date. No failure to deliver the Call Notice nor any defect therein or
in the delivery thereof shall affect the validity of the proceedings for such
redemption except as to a Holder (a) to whom a Call Notice was not delivered, or
(b) whose Call Notice was defective. An affidavit of the Secretary or an officer
of the Company that a Call Notice has been delivered in the manner provided in
Section 18(b) shall, in the absence of fraud, be prima facie evidence of the
facts stated therein.

     Any right to exercise a Warrant shall terminate at 5:00 P.M. (Arizona time)
on the Redemption Date. On and after the Redemption Date, Holders of the
Warrants shall have no further rights except to receive, upon surrender of the
Warrant, the Redemption Price.


                                       2

<PAGE>

     4. Reservation of Shares. The Company hereby agrees that at all times there
shall be reserved for issuance and delivery upon exercise of this Warrant such
number of shares of Common Stock or other shares of capital stock of the Company
as from time to time are issuable upon exercise of this Warrant. All such shares
shall be duly authorized, and when issued upon such exercise, shall be validly
issued, fully paid and non-assessable, free and clear of all liens, security
interests, charges and other encumbrances or restrictions on sale and free and
clear of all preemptive rights.

     5. Delivery of Stock Certificates. Within a reasonable time after exercise,
in whole or in part, of this Warrant, the Company shall issue in the name of and
deliver to the Holder a certificate or certificates for the number of fully paid
and nonassessable shares of Common Stock which the Holder shall have requested
in the Notice of Exercise. If this Warrant is exercised in part, the Company
shall deliver to the Holder a new Warrant for the unexercised portion of this
Warrant at the time of delivery of such stock certificate or certificates.

     6. No Fractional Shares. No fractional shares or scrip representing
fractional shares will be issued upon exercise of this Warrant. If, upon any
exercise of this Warrant, a fraction of a share results, the Company will pay
the Holder the difference between the cash value of the fractional share and the
portion of the Exercise Price allocable to the fractional share.

     7. Listing. Prior to the issuance of any shares of Common Stock upon
exercise of this Warrant, the Company shall secure the listing of such shares of
Common Stock upon each national securities exchange or automated quotation
system, if any, upon which shares of Common Stock are then listed (subject to
official notice of issuance upon exercise of this Warrant) and shall maintain,
so long as any other shares of Common Stock shall be so listed, such listing of
all shares of Common Stock from time to time issuable upon the exercise of this
Warrant; and the Company shall so list on each national securities exchange or
automated quotation system, and shall maintain such listing of, any other shares
of capital stock of the Company issuable upon the exercise of this Warrant if
and so long as any shares of the same class shall be listed on such national
securities exchange or automated quotation system.

     8. Charges, Taxes and Expenses. The Company shall pay all transfer taxes or
other incidental charges, if any, incurred or arising in connection with the
transfer of the Shares purchased pursuant to the exercise hereof from the
Company to the Holder.

     9. Loss, Theft, Destruction or Mutilation of Warrant. Upon receipt by the
Company of evidence reasonably satisfactory to it of the loss, theft,
destruction or mutilation of this Warrant, and in case of loss, theft or
destruction, of indemnity or security reasonably satisfactory to the Company,
and upon reimbursement to the Company of all reasonable expenses incidental
thereto, and upon surrender and cancellation of this Warrant, if mutilated, the
Company will make and deliver a new Warrant of like tenor and dated as of the
date of such cancellation, in lieu of this Warrant.

     10. Saturdays, Sundays, Holidays, Etc. If the last or appointed day for the
taking of any action or the expiration of any right required or granted herein
shall be a Saturday or a Sunday or shall be a legal holiday, then such action
may be taken or such right may be exercised on the next succeeding weekday that
is not a legal holiday.


                                       3

<PAGE>

     11. Adjustment of Exercise Price and Number of Shares. The Exercise Price
and the number of and kind of securities purchasable upon exercise of this
Warrant shall be subject to adjustment from time to time as follows:

          (a) Subdivisions, Combinations and Other Issuances. If the Company
shall at any time after the date hereof but prior to the expiration of this
Warrant subdivide its outstanding securities as to which purchase rights under
this Warrant exist, by stock split or otherwise, or combine its outstanding
securities as to which purchase rights under this Warrant exist, by reverse
stock split or otherwise, the number of Shares as to which this Warrant is
exercisable as of the date of such subdivision or combination will be
proportionately increased in the case of a subdivision, or proportionately
decreased in the case of a combination. Appropriate adjustments also will be
made to the Exercise Price, provided that the aggregate Exercise Price payable
for the total number of Shares purchasable under this Warrant as of such date
shall remain the same.

          (b) Stock Dividend. If at any time after the date hereof the Company
declares a dividend or other distribution on Common Stock payable in Common
Stock or Convertible Securities without payment of any consideration by such
holder for the additional shares of Common Stock or the Convertible Securities
(including the additional shares of Common Stock issuable pursuant to the terms
thereof), then the number of Shares of Common Stock for which this Warrant may
be exercised shall be increased as of the record date (or the date of such
dividend distribution if no record date is set) for determining which holders of
Common Stock shall be entitled to receive such dividend, in proportion to the
increase in the number of outstanding shares (and shares of Common Stock
issuable pursuant to the terms of the Convertible Securities) of Common Stock as
a result of such dividend, and the Exercise Price shall be adjusted so that the
aggregate Exercise Price payable for the total number of Shares purchasable
under this Warrant immediately after the record date (or on the date of such
distribution, if applicable) for such dividend will equal the aggregate Exercise
Price so payable immediately before such record date (or on the date of such
distribution, if applicable). As used herein, "Convertible Securities" means
evidences of indebtedness, shares of stock or other securities which are
convertible into or exercisable or exchangeable for, with or without payment of
additional consideration, shares of Common Stock, either immediately or upon the
arrival of a specified date or the happening of a specified event or both.

          (c) Other Distributions. If at any time after the date hereof the
Company distributes to holders of its Common Stock, other than as part of its
dissolution or liquidation or the winding up of its affairs, any shares of its
capital stock, any evidence of indebtedness or any of its assets (other than
cash, Common Stock or Convertible Securities), then the Company may, at its
option, either (i) decrease the Exercise Price of this Warrant by an appropriate
amount based upon the value distributed on each share of Common Stock as
determined in good faith by the Company's board of directors or (ii) provide by
resolution of the Company's board of directors that on exercise of this Warrant,
the Holder hereof shall thereafter be entitled to receive, in addition to the
Shares of Common Stock otherwise receivable on exercise hereof, the number of
shares or other securities or property which would have been received had this
Warrant been exercised immediately prior to the time of such distribution.


                                       4

<PAGE>

          (d) Merger. If at any time after the date hereof there shall be a
merger or consolidation of the Company with or into another corporation when the
Company is not the surviving corporation, then the Holder shall thereafter be
entitled to receive upon exercise of this Warrant, during the period specified
herein and upon payment of the aggregate Exercise Price then in effect, the
number of shares or other securities or property of the successor corporation
resulting from such merger or consolidation, which would have been received by
the Holder for the Shares subject to this Warrant had this Warrant been
exercised immediately prior to the effective time of such merger or
consolidation.

          (e) Reclassification, Etc. If at any time after the date hereof there
shall be a change or reclassification of the securities as to which purchase
rights under this Warrant exist into the same or a different number of
securities of any other class or classes, then the Holder shall thereafter be
entitled to receive upon exercise of this Warrant, during the period specified
herein and upon payment of the Exercise Price then in effect, the number of
shares or other securities or property resulting from such change or
reclassification, which would have been received by the Holder for the Shares
subject to this Warrant had this Warrant been exercised immediately prior to the
effective time of such change or reclassification.

     12. Notice of Adjustments; Notices. Whenever the Exercise Price or number
of Shares purchasable hereunder is adjusted pursuant to Section 10 hereof, the
Company must execute and deliver to the Holder a certificate setting forth, in
reasonable detail, the event requiring the adjustment, the amount of the
adjustment, the method by which such adjustment was calculated and the Exercise
Price and number of and kind of securities purchasable hereunder after giving
effect to such adjustment, and must cause a copy of such certificate to be
mailed (by first class mail, postage prepaid) to the Holder.

     13. Rights As Stockholder; Notice to Holders. Nothing contained in this
Warrant will be construed as conferring upon the Holder or his or its permitted
transferees the right to vote or to receive dividends or to consent or to
receive notice as a shareholder in respect of any meeting of shareholders for
the election of directors of the Company or of any other matter, or any rights
whatsoever as shareholders of the Company. The Company will notify the Warrant
Holder by registered mail if at any time prior to the expiration or exercise in
full of the Warrant, any of the following events occur:

          (a) a dissolution, liquidation or winding up of the Company shall be
proposed;

          (b) a capital reorganization or reclassification of the Common Stock
(other than a subdivision or combination of the outstanding Common Stock and
other than a change in the par value of the Common Stock) or any consolidation
or merger of the Company with or into another corporation (other than a
consolidation or merger in which the Company is the continuing corporation and
that does not result in any reclassification or change of Common Stock
outstanding) or in the case of any sale or conveyance to another corporation of
the property of the Company as an entirety or substantially as an entirety; or


                                       5

<PAGE>

          (c) a 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 (other than a cash dividend) or other distribution, any
right to subscribe for, purchase or otherwise acquire any shares of stock of any
class or any other securities or property, to vote upon any combination or
reverse stock split or to receive any other rights.

          Such giving of notice will be simultaneous with the giving of notice
to holders of Common Stock. Such notice must specify the record date or the date
of closing the stock transfer books, as the case may be. Failure to provide such
notice will not affect the validity of any action taken in connection with such
dividend, distribution or subscription rights, or proposed merger,
consolidation, sale, conveyance, dissolution, liquidation or winding up.

     14. Restricted Securities. The Holder understands that this Warrant and,
subject to the last sentence of this Section 13, the Shares purchasable
hereunder constitute "restricted securities" under the federal securities laws
inasmuch as they are, or will be, acquired from the Company in transactions not
involving a public offering and accordingly may not, under such laws and
applicable regulations, be resold or transferred without registration under the
Securities Act of 1933, as amended (the "1933 Act") or an applicable exemption
from such registration. Unless the Shares are subsequently registered pursuant
to Section 16 of this Warrant, the Holder further acknowledges that a securities
legend substantially similar to the securities legend set forth in the Purchase
Agreement shall be placed on any Shares issued to the Holder upon exercise of
this Warrant.

     15. Certification of Investment Purpose. Unless a current registration
statement under the 1933 Act shall be in effect with respect to the securities
to be issued upon exercise of this Warrant, the Holder covenants and agrees
that, at the time of exercise hereof, it will deliver to the Company a written
certification executed by the Holder that the securities acquired by him upon
exercise hereof are for the account of such Holder and acquired for investment
purposes only and that such securities are not acquired with a view to, or for
sale in connection with, any distribution thereof.

     16. Disposition of Shares; Transferability.

          (a) Holder hereby agrees not to make any disposition of any Shares
purchased hereunder unless and until:

               (i) Holder shall have notified the Company of the proposed
disposition and provided a written summary of the terms and conditions of the
proposed disposition; and

               (ii) Holder shall have complied with all requirements of this
Warrant applicable to the disposition of the Shares.

               The Company shall not be required (i) to transfer on its books
any Shares which have been sold or transferred in violation of the provisions of
this Section 15 or (ii) to treat as the owner of the Shares, or otherwise to
accord voting or dividend rights to, any transferee to whom the Shares have been
transferred in contravention of the terms of this Warrant.


                                       6

<PAGE>

          (b) Transfer. This Warrant shall be transferable only on the books of
the Company maintained at its principal office, wherever its principal office
may then be located, upon delivery thereof duly endorsed by the Holder or by its
duly authorized attorney or representative, accompanied by proper evidence of
succession, assignment or authority to transfer. Upon any registration of
transfer, the Company shall execute and deliver new Warrants to the person
entitled thereto.

          (c) Limitations on Transfer. This Warrant may not be sold,
transferred, assigned or hypothecated (any such action, a "Transfer") by the
Holder except to (i) one or more persons, each of whom on the date of transfer
is an officer of the Holder; (ii) a general partnership or general partnerships,
the general partners of which are the Holder and one or more persons, each of
whom on the date of transfer is an officer of the Holder; (iii) a successor to
the Holder in any merger or consolidation; (iv) a purchaser of all or
substantially all of the Holder's assets; (v) any person receiving this Warrant
from one or more of the persons listed in this Section 15(c) at such person's
death pursuant to will, trust or the laws of intestate succession, or (vi) after
one year from the date of this Warrant, any person receiving the Warrant from
the persons listed in this Section 15. This Warrant may be divided or combined,
upon request to the Company by the Holder, into a certificate or certificates
representing the right to purchase the same aggregate number of Shares. If at
the time of a Transfer, a Registration Statement is not in effect to register
this Warrant, the Company may require the Holder to make such representations,
and may place such legends on certificates representing this Warrant, as may be
reasonably required in the opinion of counsel to the Company to permit a
Transfer without such registration.

     17. Registration Rights. The Company agrees that the Shares shall be
"Registrable Securities" as such term is defined in the Registration Rights
Agreement referred to in the Purchase Agreement, and that the Holder shall be a
party to such Registration Rights Agreement on the same basis as each other
Investor named therein.

     18. Miscellaneous.

          (a) Construction. Unless the context indicates otherwise, the term
"Holder" shall include any transferee or transferees of this Warrant pursuant to
Section 15(b), and the term "Warrant" shall include any and all warrants
outstanding pursuant to this Agreement, including those evidenced by a
certificate or certificates issued upon division, exchange, substitution or
transfer pursuant to Section 15.

          (b) Notices. Unless otherwise provided, any notice required or
permitted under this Warrant shall be given in writing and shall be deemed
effectively given upon personal delivery to the party to be notified or three
(3) days following deposit with the United States Post Office, by registered or
certified mail, postage prepaid and addressed to the party to be notified (or
one (1) day following timely deposit with a reputable overnight courier with
next day delivery instructions), or upon confirmation of receipt by the sender
of any notice by facsimile transmission, at the address indicated below or at
such other address as such party may designate by ten (10) days' advance written
notice to the other parties.


                                       7

<PAGE>

          To Holder: __________________________

                     __________________________

                     __________________________

                     Attention: _______________

          To the Company: InPlay Technologies, Inc.
                          234 South Extension Road
                          Mesa, Arizona 85210
                          Attn: Chief Executive Officer
                          Facsimile: (480) 586-3326

          (c) Governing Law. This Warrant shall be governed by and construed
under the laws of the State of Arizona as applied to agreements among Nevada
residents entered into and to be performed entirely within Arizona.

          (d) Entire Agreement. This Warrant, the exhibits and schedules hereto,
and the documents referred to herein, constitute the entire agreement and
understanding of the parties hereto with respect to the subject matter hereof,
and supersede all prior and contemporaneous agreements and understandings,
whether oral or written, between the parties hereto with respect to the subject
matter hereof.

          (e) Binding Effect. This Warrant and the various rights and
obligations arising hereunder shall inure to the benefit of and be binding upon
the Company and its successors and assigns, and Holder and its successors and
assigns.

          (f) Waiver; Consent. This Warrant may not be changed, amended,
terminated, augmented, rescinded or discharged (other than by performance), in
whole or in part, except by a writing executed by the parties hereto, and no
waiver of any of the provisions or conditions of this Warrant or any of the
rights of a party hereto shall be effective or binding unless such waiver shall
be in writing and signed by the party claimed to have given or consented
thereto.

          (g) Severability. If one or more provisions of this Warrant are held
to be unenforceable under applicable law, such provision shall be excluded from
this Warrant and the balance of the Warrant shall be interpreted as if such
provision were so excluded and the balance shall be enforceable in accordance
with its terms.

          (h) Counterparts. This Warrant may be signed in several counterparts,
each of which shall constitute an original.

                         (Signatures on following page)


                                       8

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Common Stock
Warrant effective as of the date hereof.

DATED: December____, 2005        THE COMPANY:

                                 InPlay Technologies, Inc., a Nevada corporation


                                 By:
                                     -------------------------------------------
                                 Name: Robert J. Brilon, President


                                       9

<PAGE>

                               NOTICE OF EXERCISE

To: [Company Name]

          1. The undersigned hereby elects to purchase _____________ shares of
common stock, $___ par value per Share ("Stock") of ____________, a ___________
corporation (the "Company") pursuant to the terms of the attached Warrant, and
tenders herewith payment of the purchase price pursuant to the terms of the
Warrant.

          2. Please issue certificates representing the shares of Stock
purchased hereunder in the names and in the denominations indicated on Exhibit A
attached hereto.

          3. Please issue a new Warrant for the unexercised portion of the
attached Warrant, if any, in the name of the undersigned.

                                        Holder:
                                                --------------------------------

Dated:
       ----------------                 ----------------------------------------


                                        By:
                                            ------------------------------------
                                        Its:
                                             -----------------------------------


                                       10