In 2013, the city of Provo, UT built a recreation center with lots of amenities: pools, waterslides, gym, sports courts, etc. It has been used a LOT and provided a valuable resource for the families in Provo. They charge $5 a person for one-time, and have affordable monthly and family passes, which means the center has a revenue model.
Copying the Provo rec center would be less than original, but could save a lot on design work. And borrowing their financial data would provide a good estimate on the expected operations.