Tenn. Code Ann. § 37-2-302

County legislative bodies are authorized and empowered to appropriate from funds on hand not otherwise appropriated, such sums as the legislative body may deem necessary to subsidize such homes and to furnish board and care for children committed to such homes as provided in § 37-2-314; or the legislative bodies may levy a tax on property to meet such appropriations. These sums shall be paid by warrant drawn on the county treasury when proper invoice or bill has been audited and approved by the county mayor or the county mayor's designated agent.