In purchasing or otherwise acquiring surplus or donated commodities on the requisition of a school district the superintendent may advance the purchase price and other cost of acquisition thereof from the surplus and donated food commodities revolving fund and the superintendent shall in due course bill the proper school district for the amount paid by him or her for the commodities plus a reasonable amount to cover the expenses incurred by the superintendent's office in connection with the transaction. All payments received for surplus or donated commodities from school districts shall be deposited by the superintendent in the surplus and donated food commodities revolving fund.