I'm betting you'll get a better paint job from the inmates than from a cheap Maaco/Earl Sheib type place. Even with doing your own prep, they can blame their mistakes on you since they didn't do the prep. -Which I understand since they know(hopefully) what primer is compatible with the paint they use and you are only taking your best guess.
Still, I would think that cheap price would just be a single stage paint and wouldn't turn out as good as base coat/clear coat.
I like to hear about actual rehabilitation in the jails rather than inmates watching cable television, lifting weights and doing drugs. I had a former prison guard on a radio show I was part of several years back and he had some stories to tell -as well as a fifth of whiskey he was pulling on in one hand and a bag of cocaine with a straw in it in his other hand. I saw him years later in charge of inmates at our city dump and thought to myself "I bet I know how he's making some extra money."
And now I see how you have the time to look through all the Craigslists in so many cities. -You work for the government.
Don't get me wrong, I'm glad you do.
Let us see some pics when the parts are painted.