Whenever the President determines it to be consistent with and in furtherance of the purposes of this part, and on such terms and conditions consistent with this chapter as he may determine, any agency of the United States Government is authorized to furnish services and commodities, without charge to funds available to carry out this part, to an eligible foreign country, subject to payment in advance of the value thereof (within the meaning of section
2403
(m) of this title) in United States dollars by the foreign country. Credits and the proceeds of guaranteed loans made available to such countries pursuant to the Arms Export Control Act [
22 U.S.C.
2751 et seq.] shall not be used for such payments. Collections under this part shall be credited to the currently applicable appropriation, account, or fund of the agency providing such services and commodities and shall be available for the purposes for which such appropriation, account, or fund is authorized to be used.