Check out the
New Mexico State Parks Annual Pass. $225 for out-of-staters. It waives entrance fees and allows for free camping without hookups or for only $4 with hookups. I believe the only catch is that you have to leave for at least 1 night every two weeks. Most folks deal with that by going to another park for two weeks and then returning.
The southwest is a great place for boondock camping - many places where you can park your rig for free.
If you want to try some boondocking, a great resource for locating places is
The Ultimate Public Campground Project. It lists over 27,000 public camping locales in the US and Canada.
WxToad
