I am trying to work out various budgets for my two-month cross-country trip. Does anyone know the average costs for staying at a campground? I know there are different levels such as National and State, as well as private. I also know there are free campgrounds. Are these any better or worse than the ones that charge admission? Any tips on campgrounds for a first-timer would be appreciated. At this point I would probably be tenting, but it's possible too that I might be renting a camper. I don't know if that makes a difference in the price. Thanks to all of you experts!