I stayed at Canyon de Chelly for 2+ days. You can camp there for free. I ended up sleeping in my car. No problem....I'm short enough where it wasn't too much of a problem. The campground has lots of animals....dogs and cats! I had a great time here....! This is a must see - must do .... take a guided walking tour through the canyon! If you want to go into the Canyon, you must be accompanied by a Navajo Tribal Member as your official guide. You meet up with guides at the tourist info office. I don't remember the exact cost, but it was not over 15$ per person. Expect the walking tour to take up to 4-5 hours. You can take a jeep tour too, but that looked really uncomfortable and bouncy.
Please see travelogue for many many pictures!!!
more info: http://www.nps.gov/cach/