Notwithstanding any statute, public or private, providing the details of purchases on behalf of the state, or any political subdivision thereof, the state, or any political subdivision thereof, may purchase any surplus property offered for sale by the United States government from such government in such manner and on such terms as may be agreed upon between the seller and the buyer, including the right to execute deferred payment obligations and to make such purchases without taking bids or making advertisements therefor; provided, that all such purchases should be made by the agency of the state or political subdivision charged by existing or future law, with the authority to make purchases generally for the buyer.