If you're airbrushing at home noise is probably an issue. So I would suggest as has been before
http://www.everythingairbrush.com/ac...AS_Series.html I used one of these compressors at a demo for 2 days, running solidly, was okay, you need to let them cool down but when you're spraying a shell putting some paint on and then getting the hot air gun on the shell gives it time to catch up / cool down so these are okay.
http://www.everythingairbrush.com/ac...AB_AS_196.html
These airbrushes are perfectly adequate to do a shell too
http://www.everythingairbrush.com/ac...vity_Feed.html
And all that will come in well within budget.