Each person or corporation submitting a bid on real property or an interest therein to be sold or leased by the State of Alabama under this article shall present with his or her bid, payable to the Lands Division of the state Department of Conservation and Natural Resources, a certified check or bank cashier's check in the amount to be determined by the Lands Division not to exceed 20 percent of his or her bid, as a binder on the real property upon which he or she has bid. If the property is being sold at public auction, the Lands Division shall determine the amount of the binder required. The binder shall be forfeited by the person or corporation to whom the bid is awarded if the person or corporation does not complete purchase by presenting to the state a cashier's check or certified check for the amount due less the amount of the binder previously submitted on the real property within 30 days after receiving notice in writing that he or she is the successful bidder. The binder shall be applied to the purchase price of the successful bid. The Director of the Lands Division for good cause shown may extend the period for completing the sale for one additional period of seven days. Certified checks submitted as binders by those persons or corporations not awarded the bid shall be returned to the persons or corporations.