Before you give into the belief that you cannot afford an airbrush, check out the sets being offered by Lindberg/Hawk. If you don't have a compressor, there is canned air, a portable air tank (used to fill tires) and I've believe it or not once used an old spare car tire filled to capacity...it was enough to lay a quick base coat of OD on a model. I did it to prove the idea worked as well as to demonstrate several uses for a spare tire...did you know they make great rescue floatation devices too?
A beginners airbrush is no more than the price of a median priced model these days.