In Michigan you have several different types of launches. You have state launches, county launches, city launches, private launches, and public launches.
The state charges two ways: 1. a yearly fee that can be paid when you purchase your vehicle tags (10-12 bucks per year). This allows you to use ALL state launches (which most in Michigan are). You can pay by the day (not sure on the fee but after a couple times you pay more than the yearly pass).
City and county launches are up kept by the city or county. They can charge whatever they want. Some have a yearly access pass, some do not. Some have good launches and parking, some do not. Public launches are usually owned by county or city but they do not charge to use. First come, first serve basically.
Private launches are just that. Owned by a Marina or other municipality. I am a member of a private launch on the Detroit river. It costs me $100 dollars per year. Small price to pay when others are waiting in line to launch for up to two hours at a time.