From what little experience I have with airbrushing a project here and there over the years, I'd have to say that tiki's advice above is sound. That being said, I used to have a badger 150 and now have a 155 and quite liked both of them--relatively inexpensive, sprays accurately and cleanly enough that my lack of skill is the limiting factor, not the equipment
, and parts are cheap and available if you wear out or break something. If upfront $$ is an issue, the badgers can usually be had cheaper, but I have no experience with the iwata line, so I won't try to tell you which is a better value. Just my 2 cents.