I guess I'm a little jaded from living in MA. When my other son went to U Mass Amherst, the tuition was 6k a year, but now it's 10K. I guess it's high compared to other places, but he got a really good education. And since most of the people here go to private universities and pay at least 30k a year just for tuition, it seems like nothing. I just saw on the news that the tuition in CA is going up to 10K. People here would think that was a deal! I'm in grad school for a second master's at a private university and I am paying about $900 a credit... total program is 60 credits, so do the math. I got a loan as I wasn't willing to give up my life style. I will pay it back when I start working again, although having a spouse certainly helps. Have you looked into grad assistantships? I was in a PhD program at ASU and I didn't pay a dime (I quit because I was sick of school at the time).

One suggestion about AZ. Why would you be taking non degree courses? I seem to remember that you could take summer classes for in state tuition, no matter where you were from. Since there are 2 5 week summer sessions, it could be up to 12 credits. Of course, you have to be able to stand the heat!
Also, a lot of people moved there, got a job to establish residency, a driver's license, etc and went part time. I also think you can take up to 6 credits for in state tuition. If you are planning to take a year off, why not move, get your residency if that is the program you really want to do.