>>1244301Most national forests in America don't charge you for camping, if you're doing it primitive style. They just require you to pack out everything you bring it, and be aware of the fire policy that may change on a daily basis.
Typically, the only charge I run into is for parking, which is like 3-5 bucks a night. Nothing to cry over.
If you're using a dedicated site at a recreation center that's usually on either end of a trail, however, they will usually charge to camp there, as it's a privately owned business that built and managed that particular area.