Have you picked out a brush yet?
I started with a super cheap, $20 Badger I bought at Michaels. It was so bad and hard to use, I'm surprised I stuck with airbrushing. I eventually upgraded to a Badger Crescendo because I had a great coupon. Every once in a while, Michaels has a 50 or 60% off coupon, which makes this brush very affordable for a beginner. When I bought a brush for my BFF who's just starting out, I bought a Crescendo.
The Crescendo is a bottom-feed brush, which means the paint gets pulled up from a bottle below the brush. These kinds of brushes get clogged more often, although they don't bother me as I've very used to working with them. The opposite is a gravity feed, with the paint on top. I don't recommend them for beginners, but I own an Iwata BCS and an Iwata Micron. They are fantastic brushes, but a big investment if you don't know if you're going to stick with airbrushing.
I use Golden Acrylics mixed with Pearl Ex pigments to paint and water them down. I paint a lot and one tube of paint will usually last a few years. I've never had to buy a replacement tub of Pearl Ex. They last forever.
Spare bottles for paint and a compressor are a must. If you can, look for an airbrush with variable pressure, although I don't have one myself. I also have a bunch of
those little brushes to clean braces to get blockages out.
I have a MLP I just finished with an airbrush, but it's a gift and I'm paranoid the receiver will see it if I post it here.

But these guys are all airbrush, plus the gal in my avatar:
