You've come to the right place for airbrush advice. These guys know whereof they speak!
I agree with the recommendations above, but I'll throw in my
just to make your choice more difficult.
(Sorry about that, but there are a lot of good choices.) I "learned"* on a Paasche H—Simple, easy to clean, and sturdy. Double actions have this long, very sharp, incredibly delicate needle that has to be threaded through the whole length of the airbrush without damage—it is the only thing I really don't like about double actions. The Paashe H single action has a comparatively sturdy and solid needle and paint cone. If you do buy one, plan on replacing the stupid, tiny set screw that holds the needle-cone assembly in the frame with a short, wide headed screw.
Now that I've bought a double action (Thayer & Chandler Omni 4000), I think that the admonition to start with a single action airbrush because it is simpler and therefore easier to learn is overcautious. Anyone capable of assembling a detailed 1/72 scale kit has the physical dexterity to handle a double action.
Just my
.
*You never stop learning to use an air brush! Don't let this intimidate you!