I'm a combo Mike Brewer / Edd China wannabe and I've found the sweetspot for pricing a car competively is 1/2 way between Retail & Clean Trade In on NADA. You as a private seller can't get retail like a dealer, so you have to charge less. I've found the above formula is about where the public will bite on a private sale. Caution: current prices listed will still have good weather factored in, since their data is from dealer car sales and it's not real time - there is a lag factor. So any pricing guide is a shade behind the current mkt. I imagine the weather factor is less in AZ, but you'll need to factor it in if you intend to sell nationally.
I also like to look at AutoTrader and sometimes Cars.com (they have lots of fake ads) too to get a feel for pricing.
And then this link will give you a good idea and is a good way to spend an hr or 2.
Rideslist.com - car classifieds (sfbay)