§ 6404. Purchases by certain independent institutions. Any postsecondary institution chartered under the powers of the regents pursuant to § 216 of the state finance law which may establish limitations with respect to commodities and services and impose such other appropriate conditions upon purchasing as deemed necessary by the commissioner of general services in order to protect the state's own purchasing interests; provided that each such purchase shall have a cost of five hundred dollars or more and that said institution shall accept sole responsibility for any payment of such cost due the vendor.