<PAGE>

CONFIDENTIAL TREATMENT HAS BEEN REQUESTED FOR CERTAIN REDACTED PROVISIONS OF
THIS AGREEMENT. THE REDACTED PROVISIONS ARE IDENTIFIED BY THREE ASTERISKS
ENCLOSED BY BRACKETS AND UNDERLINED. THE CONFIDENTIAL PORTION HAS BEEN FILED
SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION.

                                                                    EXHIBIT 10.6
                           NON-COMPETITION AGREEMENT


          This Non-Competition Agreement (this "Agreement") is entered into
effective as of April 26, 2000 by and between BUYNOW INC., a Delaware
corporation ("BUYNOW"), and BUY.COM INC., a Delaware corporation (together with
any of its subsidiaries, subdivisions or affiliates other than BUYNOW, the
"Company" or "BUY.COM").

                                R E C I T A L S

          WHEREAS, BUYNOW is a wholly owned subsidiary of the Company;

          WHEREAS, the Company intends to spin-off BUYNOW by way of a dividend
distribution of 100% of the shares of the Common Stock of BUYNOW to the
Company's stockholders (the "Spin-Off");

          WHEREAS, the Spin-Off was approved only upon the condition that BUYNOW
agree to refrain from certain activities as set forth below; and

          WHEREAS, it is a condition to the Spin-Off that BUYNOW memorialize its
agreement to refrain from said activities by entering into this Agreement with
BUY.COM and adhere to its terms.

                               A G R E E M E N T

          NOW, THEREFORE, in consideration of the mutual covenants in this
Agreement and other good and valuable consideration, intending to be legally
bound, the parties agree as follows:

      1.  Non-Solicitation.  BUYNOW will not, directly or indirectly, knowingly
          ----------------
employ, or knowingly permit any other company or business organization which is
directly or indirectly controlled by BUYNOW to employ, any person while that
person is employed by the Company, or in any manner seek to induce any person
currently employed by the Company to leave his or her employment with the
Company, without the prior written consent of the Company.

      2.  Provision of Services to [***].  BUYNOW has not, and will not, without
          ------------------------------
the prior written consent of the Chief Executive Officer of the Company, provide
or agree to provide, directly or indirectly, its services or technology of any
type to a "Restricted Business." A "Restricted Business" is any company or
entity engaged in, or intending to become engaged in, [***], other than (i)
companies or entities engaged solely in the [***]; (ii) companies or entities
whose primary business is to [***]; or (iii) companies or entities that operate
[***.]

      3.  Equitable Relief.  BUYNOW agrees that any material breach of this
          -----------------
Agreement by it will cause irreparable damage to the Company and that in the
event of such breach the Company shall have, in addition to any and all remedies
of law, the right to an injunction,

specific performance or other equitable relief to prevent the violation of
BUYNOW's obligations hereunder.

[***] Confidential treatment has been requested for the bracketed portions. The
confidential redacted portion has been omitted and filed separately with the
Securities and Exchange Commission.
<PAGE>

      4.  Amendment.  Any amendment to or modification of this Agreement, and
          ---------
any waiver of any provision hereof, shall be in writing executed by the Chief
Executive Officer of each party. Any waiver of a breach of any provision of this
Agreement shall not operate or be construed as a waiver of any subsequent breach
hereof.

      5.  Severability; Modification.  Each party hereby agrees that each
          --------------------------
provision herein shall be treated as a separate and independent clause, and the
unenforceability of any one clause shall in no way impair the enforceability of
any of the other clauses herein. Moreover, if one or more of the provisions
contained in this Agreement shall for any reason be held to be excessively broad
as to scope, activity or subject so as to be unenforceable at law, such
provision or provisions shall be construed by the appropriate judicial body by
limiting and reducing it or them, so as to be enforceable to the maximum extent
compatible with the applicable law as it shall then appear.

      6.  Assignment.  BUY.COM shall have the right to assign this Agreement to
          ----------
its successors and assigns, and all covenants and agreements hereunder shall
inure to the benefit of and be enforceable by said successors or assigns;
provided that such assignment does not expand the scope or coverage of this
Agreement.

      7.  Entire Agreement.  This Agreement constitutes the entire agreement
          ----------------
between the parties with respect to its subject matter and supersedes any other
prior or contemporaneous agreements or understandings, oral or written, between
the parties with respect to that subject matter.

      8.  Governing Law.  This Agreement shall be governed by and construed in
          -------------
accordance with the laws of the State of Delaware, without giving effect to the
conflict of law principles thereof.

      9.  Effect of Headings.  The headings contained in this Agreement are for
          ------------------
reference purposes only and shall not affect in any way the meaning or
interpretation of this Agreement.

      10. Confidentiality.  This Agreement and its contents are confidential and
          ---------------
shall remain confidential following its execution.  No party hereto shall
knowingly make any disclosure of the existence or the terms of this Agreement or
provide an original or copy of all or any portion thereof to anyone, except in
compliance with a lawful order or process of a court or arbitrator of competent
jurisdiction or governmental agency, or as may otherwise be required by law or
regulation, or with the written consent of all other parties hereto, or in
connection with (i) any financing event in which BUYNOW is trying to issue
equity securities to a third party investor or (ii) the filing of a Registration
Statement on Form S-1, including any amendments thereto, by either party with
the Securities and Exchange Commission.

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<PAGE>

          IN WITNESS WHEREOF, the parties hereto have executed this Non-
Competition Agreement as of the date first above written.

                                    BUY.COM INC.


                                    By:_____________________________
                                       Name:
                                       Title:


                                    BUYNOW INC.


                                    By:_____________________________
                                       Name:
                                       Title:



                 [Signature page to Non-Competition Agreement]

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