Miss. Code Ann. § 31-7-103

The purchase clerk shall be responsible as hereinafter provided for the purchase and acquisition of all equipment, heavy equipment, machinery, supplies, commodities, materials and services to be acquired for the county from successful bidders or other vendors, as authorized by law. The central purchase system shall comply with the requirements prescribed by the State Department of Audit under the authority of Section 7-7-211 and in accordance with Section 31-7-113, and the purchase clerk shall be responsible for the maintenance of such system. No requisition to purchase, purchase order or receiving report shall be required for the purchase of any item or services with an acquisition cost of not more than One Thousand Five Hundred Dollars ($1,500.00) in the aggregate; however, the invoice for every such purchase shall be signed by the department head or his or her designee, or a receipt signed by the person making the purchase shall be attached to the invoice and forwarded to the purchase clerk.No claim based on any such purchase shall be approved except after compliance with the provisions of this section.