Monthly rates at sun community park

I think they are collecting "option" money from you. They are reserving a spot for you and charging you a fee "option" payment each month. When you use the site the option money is credited to your bill for the site. This is done all the time in real estate. You buy an option to possibly purchase a property in X months. You may pay the option once, monthly or whatever. If you buy the property, all or a portion is applied to the purchase price. If you decide not to buy, you lose your option money. They are running the risk you will not show up to complete the rental and want to encourage you to show up. If you have money to lose, you are less likely not to fulfill your reservation. Nothing illegal about protecting yourself as the campground owner.