There are so many variables with camping. We had a popup for 9 years, and spent 20-30 nights a year in it. We bought it slightly used for $6k, and sold it for $5k. No question, it more than paid for itself. Last summer we upgraded to a new TT, but with what we've save in cost over those 9 years, we are in good shape.
Also we've realized that we like the places we can go in the camper much better than a hotel or condo. Our teenage kids go on a beach trip with the church each summer, and stay in a condo, and both say they prefer the camper. Our daughter turns 16 this spring, and has asked for her sweet 16 to take some of her friends camping in the mountains. Lots of her friends have plans that involve limos and fancy restaurants, this makes me feel like we might have done the right thing with camping.