Air brush for Noobs. Which one do you use?

What kind of air brush do you use?
I never used/seen any one before.. I am looking to buy one..
I don't want to spend a lot of money ($150+)
but I want something I can still use when I get a lot better at this modeling(quality piece).
Any recommendations?

Also is there a good FAQ for how to use a airbrush?

How to Use an Airbrush by Robert Downie (http://www.amazon.com/exec/obidos/tg/detail/-/0890242879/ref=pd_sim_art_elt/103-6101528-3839009?v=glance)

I would go for the AZTEK A4709 its a great airbrush i got mine from ebay and an air compressor for 170 including shipping and handeling. EBAY has some good items right now!!!