Any agency may purchase used equipment or other materiel by negotiated purchase, rather than by competitive bidding, as provided in this chapter, if it is demonstrated to the satisfaction of the agency head that the negotiated price is reasonable for the intended use. The contracting agency shall use lifecycle costing analysis as specified in §§ 6902 and 6909A(b) of this title prior to demonstrating to the agency head that the negotiated price is reasonable for the intended use.