The best prices on air brushes I have found is a place right here in my home town. They also have a hugh internet presence. When I was searching/researching product and price, I ran across them. I have the Iwate Eclipse HP-BCS and have been pleased with it.
http://www.dixieart.com/Eclipse.html
They also handle AutoAir colors at very good prices. These are water based/automotive grade paints used by professional custom painters and do a fine job on my boats. I use a good clear over them and it's a wrap. They are easy to deal with and easy to clean up and have a good color selection, too. Check 'em out.
http://www.dixieart.com/CreatexAutoAir.html