Now, for the other side of the story.
I painted my bus myself,,, three times trying to get it right. It still sucks,,, of course for 50 yards away it looks great. Up close is another story. There are many things that can go wrong for a newbie. Paint mix,,, paint gun,,, air pressure,,,, laying down the paint with the correct mix, air and motions can be a real learning curve. Cheap paint guns are just that, cheap,,, I had one fail, after I had mixed $200 worth of paint.
Would suggest before you go spending 400-600 on primer, and paint, that you hire someone,,,, (a good friend is better) that knows how to paint. He can shorten the learning curve by hundreds of $$$$$$$ If you do all the prep work, the sanding, body work if needed, removing trim, etc,,,, you should be able to find someone to help for under $500.00.. If you ask me, that is money well spent.
Good Luck,
Bill