40 U.S.C. § 503

(a) Authority of Executive Agencies .— In acquiring personal property, an executive agency may exchange or sell similar items and may apply the exchange allowance or proceeds of sale in whole or in part payment for the property acquired. (b) Applicable Regulation and Law.— (1) Regulations prescribed by administrator of general services .— A transaction under subsection (a) must be carried out in accordance with regulations the Administrator of General Services prescribes, subject to regulations prescribed by the Administrator for Federal Procurement Policy under division B (except sections 1704 and 2303) of subtitle I of title 41. (2) In writing .— A transaction under subsection (a) must be evidenced in writing. (3) Section 6101( b ) to ( d ) of title 41 .— Section 6101(b) to (d) of title 41 applies to a sale of property under subsection (a), except that fixed price sales may be conducted in the same manner and subject to the same conditions as are applicable to the sale of property under section 545(d) of this title .