Mayors only get paid for the time they are Mayor for the town or city.
Once the mayor's term is up then the mayor of the town or city no longer gets any pay from the city or town.
However in some larger cities the mayor may get a pension and get paid during retirement.
Also being a mayor is hard work and you need to know a lot of things about city and government to handle being a mayor of a town and a city.
You have to attend city and town meetings and discuss things about improving the city or town and listen to people in the town complain to you about things.
Mayors in smaller towns do not earn much money but mayors in larger cities may earn around $3,000.00 to as much as $10,000.00 per month.