Except as otherwise provided in section 40-40-18, no municipal expenditure may be made nor liability incurred, and no bill may be paid for any purpose in excess of the appropriation made therefor in the final budget. Expenditures made, liabilities incurred, or warrants issued in excess of the appropriations are a joint and several liability of the members of the governing body who authorized the making, incurring, or issuing thereof or who were present when they were authorized and did not vote against authorizing the same.