Now that you've had a chance to read up on the subject, and let us know you're on a pension I have a suggestion for you.
Badger has a "garage" sale page, that has some pretty good deals. If you are comfortable to shop online I would look into this deal.
http://www.badgerairbrush.com/garagesale.htm
Scroll down about half way to find:
Thayer & Chandler dual action bottom feed with trigger range setting handle $30
About three quarters down:
Badger 10' Braided Hose w/moisture trap: $6
and a bit more:
Thayer & CHandler rebuilt compressor $99
Grand total of $135, plus any taxes and shipping gets you set up for about the same price as a compressor alone.
If you wanted a gravity fed brush, forego the T&C I mentioned above and buy the Badger 100LG (medium tip) from Dixie Art $69.95 delivered. That would raise your budget to $175, but would give you an outstanding airbrush.