No officer of a city of the primary class shall receive any pay or perquisite from the city other than his or her salary, and the city council shall not pay or appropriate any money or other valuable thing to any person, not an officer, for the performance of any act, service, or duty, the performance of which shall come within the proper scope of the duties of any officer of the city, unless such money or other valuable thing is specifically appropriated and ordered by unanimous vote of all members elected to the city council.