Expenditures of the city funds of the payment of any claim against the city shall be lawfully made on the basis of the amount provided therefor in the annual city budget and claims against the city shall be allowed on the basis of appropriations made from time to time by the commission. The city manager shall cause appropriation ordinances to be prepared showing the amount to be expended and the purpose of the expenditure. Upon allowance of the claims, the same shall be paid as hereinafter provided. (Prior code § 1-407)