If you can get by with masking, just about any airbrush will lay down a nice coat of paint. The first airbrush I owned was a really cheap Testors set that I picked up about twelve years ago at a local drug store for under twenty bucks.
The thing works like a miniaturized garden sprayer and has no control in terms of doing free-hand camo. With its wider spray pattern, it also does waste some paint. On the other hand, it really cannot clog, cleaning is trivial, and with paint properly thinned paint, it puts down a coat of paint that's as nice as any of my more expensive airbrushes. Although I have retired the thing, if I were living a really tight budget, I probably would still be happily using it today.
