<PAGE>

                                                                     Exhibit 4.3

           THIS WARRANT AND THE SECURITIES ISSUABLE UPON THE EXERCISE
           HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
           1933. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED,
           HYPOTHECATED, OR OTHERWISE TRANSFERRED EXCEPT PURSUANT TO AN
           EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF
           1933, OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY
           THAT REGISTRATION IS NOT REQUIRED UNDER SUCH ACT OR UNLESS
           SOLD PURSUANT TO RULE 144 UNDER SUCH ACT.

           No. W-_______

                        WARRANT TO PURCHASE COMMON STOCK
                                       OF
                               TRADEOUT.COM, INC.

                           VOID AFTER OCTOBER 18, 2001

                  This Warrant is issued to __________, or its registered
assigns ("Holder") by TradeOut.com, Inc., a Delaware corporation (the
"Company"), on October 18, l999 (the "Warrant Issue Date").

                  With respect to the persons and entities set forth under the
heading "Series C Investors' on Schedule A hereto, this Warrant is issued to
such Holder pursuant to the terms of that certain Series C Preferred Stock and
Warrant Purchase Agreement dated as of the date hereof (the "Purchase
Agreement").

                  With respect to the persons and entities set forth under the
heading "Series A investors" on SCHEDULE A hereto, this Warrant is issued to
such Holder as an amendment and restatement of the warrant issued to such Holder
pursuant to that certain Warrant Agreement dated as of April 19, 1999 (the
"Existing Warrant Agreement"). In consideration of the transactions contemplated
by the Purchase Agreement and other good and valid consideration, such Holder
represents, warrants and agrees that it has submitted for cancellation the
warrant that such Holder received pursuant to the Existing Warrant Agreement and
that this Warrant amends and restates such warrant in its entirety. Such Holder
represents, warrants and agrees that the Existing Warrant Agreement has been
terminated and is of no further force and effect.

                  Collectively,  the Warrants  referred to in the  preceding two
paragraphs shall be referred to as the "Warrants."

                  1.   PURCHASE  SHARES. Subject to the terms and conditions
hereinafter set forth and set forth in the  Purchase  Agreement, the Holder
is entitled, upon surrender of this Warrant at the principal office of the
Company (or at such other place as the Company shall notify the holder hereof
in writing), to purchase from the Company up to ___________ (         ) fully
paid and nonassessable shares of

<PAGE>

Common  Stock of the  Company,  as  constituted  on the Warrant  Issue Date (the
"Common Stock").  The number of shares of Common Stock issuable pursuant to this
Section 1 (the  "Shares")  shall be subject to adjustment  pursuant to Section 8
hereof.

                       (a) EXERCISE PRICE. The purchase price for the Shares
shall be $3.97691828, as adjusted from time to time pursuant to Section 8 hereof
(the "Exercise Price").

                  2.   EXERCISE  PERIOD.  This Warrant shall be  exercisable,
in whole or in part, during the term commencing on the Warrant Issue Date and
ending at 5:00 p.m. on the earlier of (i) October 18, 2001 or (ii) the date that
is ninety (90) days after the closing of the Company's sale of its Common Stock
in a firm commitment underwritten public offering pursuant to a registration
statement on Form S-1 or Form SB-2 under the Securities Act of 1933, as amended,
the public offering price of which was not less than $20,000,000 in the
aggregate.

                  3.   METHOD OF EXERCISE. While this Warrant remains
outstanding and  exercisable in accordance with Section 3 above,  the Holder may
exercise,  in whole or in part,  the  purchase  rights  evidenced  hereby.  Such
exercise shall be effected by:

                       (a) the  surrender of the Warrant,  together  with a duly
executed  copy  of the  form of  Notice  of  Election  attached  hereto,  to the
Secretary of the Company at its principal offices; and

                       (b) the payment to the Company of an amount  equal to the
aggregate Exercise Price for the number of Shares being purchased

                  4.   NET EXERCISE. In lieu of exercising this Warrant pursuant
to Section 4, the Holder may elect to receive, without the payment by the Holder
of any  additional  consideration,  shares of Common Stock equal to the value of
this  Warrant (or the portion  thereof  being  canceled)  by  surrender  of this
Warrant at the  principal  office of the  Company  together  with notice of such
election,  in which event the Company  shall issue to the holder hereof a number
of shares of Common Stock computer using the following formula:

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

         Where:     X  =     The number of shares of Common Stock to be issued
                             to the Holder pursuant to this net exercise;

                    Y  =     The number of Shares in respect of which the net
                             issue election is made;

                    A =      The fair market value of one share of the Common
                             Stock at the time the net issue election is made;

                    B =      The Exercise Price (as adjusted to the date of the
                             net issuance).

For purposes of this Section 5, the fair market value of one share of Common
Stock as of a particular date shall be determined as follows: (i) if traded on a
securities exchange or through


                                       2
<PAGE>

the National Market,  the value shall be deemed to be the average of the closing
prices of the securities on such exchange over the thirty (30) day period ending
three  (3)  days   prior  to  the  net   exercise   election;   (ii)  if  traded
over-the-counter, the value shall be deemed to be the average of the closing bid
or sale prices  (whichever is applicable) over the thirty (30) day period ending
three (3) days prior to the net exercise; and (iii) if there is no active public
market, the value shall be the fair market value thereof,  as determined in good
faith by the Board of Directors of the Company. The right of the Holder to elect
to net exercise this Warrant pursuant to this Section 5 shall terminate upon the
date that is ninety (90) days  following the Company's  closing of a sale of its
Common Stock in a firm commitment  underwritten  public  offering  pursuant to a
registration  statement on Form S-1 or Form SB-2 (or any  successor  form) under
the Securities Act of 1933, as amended,  the public  offering price of which was
not less than  $20,000,000  in the aggregate.  The preceding  sentence shall not
terminate  or  modify  the  Holder's  right to elect to  exercise  this  Warrant
pursuant to Section 4.

                  5.   CERTIFICATES FOR SHARES. Upon the exercise of the
purchase  rights  evidenced by this Warrant,  one or more  certificates  for the
number of Shares so purchased shall be issued as soon as practicable  thereafter
(with appropriate  restrictive legends, if applicable),  and in any event within
thirty (30) days of the delivery of the subscription notice.

                  6.   ISSUANCE OF SHARES. The Company covenants that the
Shares,  when issued pursuant to the exercise of this Warrant,  will be duly and
validly issued, fully paid and nonassessable and free from all taxes, liens, and
charges with respect to the issuance thereof.

                  7.   ADJUSTMENT  OF  EXERCISE PRICE AND NUMBER OF SHARES.  The
number of and kind of securities  purchasable  upon exercise of this Warrant and
the Exercise Price shall be subject to adjustment from time to time as follows:

                       (a)  SUBDIVISIONS,  COMBINATIONS AND OTHER ISSUANCES.  If
the Company shall at any time prior to the expiration of this Warrant  subdivide
its Common Stock, by split-up or otherwise or combine its Common Stock, or issue
additional  shares of its Common  Stock or  Preferred  Stock as a dividend  with
respect to any shares of its Common Stock,  the number of Shares issuable on the
exercise of this Warrant  shall  forthwith be  proportionately  increased in the
case of a subdivision or stock  dividend,  or  proportionately  decreased in the
case  of a  combination.  Appropriate  adjustments  shall  also  be  made to the
purchase price payable per share,  but the aggregate  purchase price payable for
the total number of Shares  purchasable  under this Warrant (as adjusted)  shall
remain the same. Any adjustment  under this Section 8(a) shall become  effective
at the close of  business on the date the  subdivision  or  combination  becomes
effective,  or as of the record date of such  dividend,  or in the event that no
record date is fixed, upon the making of such dividend.

                       (b)  RECLASSIFICATION,  REORGANIZATION AND CONSOLIDATION.
In case of any reclassification, capital reorganization, or change in the Common
Stock of the Company (other than as a result of a subdivision,  combination,  or
stock dividend provided for in Section 8(a) above), then, as a condition of such
reclassification, reorganization, or change, lawful provision shall be made, and
duly executed  documents  evidencing  the same from the Company or its successor
shall be delivered to the Holder, so that the Holder shall have the right at any
time prior to the expiration of this Warrant to purchase, at a total price equal
to that payable upon the


                                       3
<PAGE>

exercise  of this  Warrant,  the kind and  amount  of  shares of stock and other
securities  and property  receivable in connection  with such  reclassification,
reorganization,  or change  by a holder  of the same  number of shares of Common
Stock  as  were   purchasable   by  the   Holder   immediately   prior  to  such
reclassification,  reorganization,  or  change.  In any  such  case  appropriate
provisions  shall be made with  respect to the rights and interest of the Holder
so that the provisions hereof shall thereafter be applicable with respect to any
shares of stock or other  securities  and  property  deliverable  upon  exercise
hereof,  and  appropriate  adjustments  shall be made to the purchase  price per
share payable hereunder,  provided the aggregate purchase price shall remain the
same.

                       (c) NOTICE OF ADJUSTMENT. When any adjustment is required
to be made in the  number or kind of shares  purchasable  upon  exercise  of the
Warrant,  or in the Warrant Price,  the Company shall promptly notify the holder
of such event and of the number of shares of Common Stock or other securities or
property thereafter purchasable upon exercise of this Warrant.

                  8.   NO FRACTIONAL SHARES OR SCRIP. No fractional shares or
scrip representing fractional shares shall be issued upon the exercise of this
Warrant, but in lieu of such fractional shares the Company shall make a cash
payment therefor on the basis of the Exercise Price then in effect.

                  9.   NO STOCKHOLDER RIGHTS. Except as otherwise provided in
the Purchase Agreement, the Restated Certificate (as defined in the Purchase
Agreement), the Investors' Rights Agreement (as defined in the Purchase
Agreement) the Co-Sale Agreement (as defined in the Purchase Agreement) or
herein, prior to exercise of this Warrant, the Holder shall not be entitled to
any rights of a stockholder with respect to the Shares, including (without
limitation) the right to vote such Shares, receive dividends or other
distributions thereon, exercise preemptive rights or be notified of stockholder
meetings, and such holder shall not be entitled to any notice or other
communication concerning the business or affairs of the Company.

                  10.  TRANSFERS OF WARRANT. Subject to compliance with
applicable federal and state securities laws, this Warrant and all rights
hereunder are transferable in whole or in part by the Holder to any person or
entity upon written notice to the Company. The transfer shall be recorded on the
books of the Company upon the surrender of this Warrant, properly endorsed, to
the Company at its principal offices, and the payment to the Company of all
transfer taxes and other governmental charges imposed on such transfer. In the
event of a partial transfer, the Company shall issue to the holders one or more
appropriate new warrants.

                  11.  SUCCESSORS AND ASSIGNS. The terms and provisions of this
Warrant and the Purchase Agreement shall inure to the benefit of, and be binding
upon, the Company and the Holders hereof and their respective successors and
assigns.

                  12.  AMENDMENTS AND WAIVERS. Any term of this Warrant may be
amended and the observance of any term of this Warrant may be waived (either
generally or in a particular instance and either retroactively or
prospectively), with the written consent of the Company and the holders of
seventy percent (70%) of the shares of Common Stock issued or issuable upon
exercise of the Warrants. Any waiver or amendment effected in accordance with
this Section shall be binding upon each holder of any Shares purchased under
this Warrant at the time


                                       4
<PAGE>

outstanding (including securities into which such Shares have been converted),
each future holder of all such Shares, and the Company.

                  13.  EFFECT OF AMENDMENT OR WAIVER. The Holder acknowledges
that by the operation of Section 13 hereof, the holders of seventy percent (70%)
of the shares of Common Stock issued or issuable upon exercise of the Warrants,
will have the right and power to diminish or eliminate all rights of such holder
under this Warrant or under the Purchase Agreement.

                  14.  ASSUMPTION OF WARRANT. If at any time, while this
Warrant, or any portion thereof, is outstanding and unexpired there shall be (i)
the acquisition of the Company by another entity by means of any transaction or
series of related transactions (including, without limitation, any
reorganization, merger or consolidation) that results in the transfer of fifty
percent (50%) or more of the outstanding voting power of the Company or (ii) a
sale of all or substantially all of the assets of the Company, then, as a part
of such acquisition, sale or transfer, lawful provision shall be made so that
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 (including by net exercise), the number of shares of stock
or other securities or property of the successor corporation resulting from such
acquisition, sale or transfer which a holder of the shares deliverable upon
exercise of this Warrant would have been entitled to receive in such
acquisition, sale or transfer if this Warrant had been exercised immediately
before such acquisition, sale or transfer, all subject to further adjustment as
provided in this Section 15; and, in any such case, appropriate adjustment (as
determined by the Company's Board of Directors) shall be made in the application
of the provisions herein set forth with respect to the rights and interests
thereafter of the Holder to the end that the provisions set forth herein
(including provisions with respect to changes in and other adjustments of the
number of Warrant Shares of the Holder is entitled to purchase) shall thereafter
by applicable, as nearly as possible, in relation to any shares of Common Stock
or other securities or other property thereafter deliverable upon the exercise
of this Warrant.

                  15.  NOTICES. All notices required under this Warrant and
shall be deemed to have been given or made for all purposes (i) upon personal
delivery, (ii) upon confirmation receipt that the communication was successfully
sent to the applicable number if sent by facsimile; (iii) one day after being
sent, when sent by professional overnight courier service, or (iv) five days
after posting when sent by registered or certified mail. Notices to the Company
shall be sent to the principal office of the Company (or at such other place as
the Company shall notify the Holder hereof in writing). Notices to the Holder
shall be sent to the address of the Holder on the books of the Company (or at
such other place as the Holder shall notify the Company hereof in writing).

                  16.  ATTORNEYS' FEES. If any action of law or equity is
necessary to enforce or interpret the terms of this Warrant, the prevailing
party shall be entitled to its reasonable attorneys' fees, costs and
disbursements in addition to any other relief to which it may be entitled.

                  17.  CAPTIONS. The section and subsection headings of this
Warrant are inserted for convenience only and shall not constitute a part of
this Warrant in construing or interpreting any provision hereof.


                                       5
<PAGE>

                  18.  GOVERNING LAW. This Warrant shall be governed by the laws
of the State of New York as applied to agreements among New York residents made
and to be performed entirely within the State of New York.

                  IN WITNESS WHEREOF, TradeOut.com, Inc. caused this Warrant to
be executed by an officer thereunto duly authorized.

                                   TRADEOUT.COM, INC.

                                   By: /s/ B McCagg
                                       _________________________________________
                                   Title:  President and Chief Executive Officer


                                       6
<PAGE>

                                   SCHEDULE A

SERIES C INVESTORS

Benchmark Capital Partners IV, L.P.
eBay, Inc.

SERIES A INVESTORS

Catterton-Simon Partners III, L.P.
JFI-TO, L.L.C.
GFI-TO, L.L.C.
Channel-TO, L.L.C.
Jules Reich
MRB Holding Co., LLC
Gerald Rosenfeld
Fairbairn Trust Company Limited as Trustees of the Gadjzus Trust
Interlink Metals and Chemicals S.A.
Allison K. Stilp
David F. Cary


                                       7