>>1146364LOL
Most of the west is BLM land which means it is owned by the government and available for multiple uses, including free camping. For instance, when you go to Arches NP, there's a BLM dirt road just north of the entrance that has loads of pull-outs for camping with fire pits usually already set up. You just have to be careful with how many unpaved roads there are out west. Don't risk a sketchy road in that minivan, heh... Pic related is a map of Moab and the camping availability, for example. So all the green striped areas are free camping, and are right near Arches. Can't really beat that, since camping in the national parks will be hit or miss.
freecampsites.net is a website you should bookmark right now because you'll find that free camping in that minivan will be the ultimate option. I go car camping all over the west, and don't pay a dime usually to see dozens of national parks. Most have free camping/BLM land right nearby. That's just how the west is.