Depends on the model of airbrush it is, and what else is with it - some have only a few tips and one cup, others have 6 tips, 3 cups and 2 jars, etc.
Here in Oz, the top model A4709 goes for up to AUD $299 (about USD $195) but I got mine for $250 after negotiation. Lots of sites where you can buy off the net. Suggest you check out there for the price for the specific type you are looking at.
Lots of guys love the Aztek (including me) but lotsa others hate them. If you are new to airbrushing it may take some practice to get the right results from this brush. If you do get it...make sure you watch the instructional video. Most guys just jump in, and don't know how to use it properly or care for it. Most problems are really missuse (sorry Paasche and Badger guys!!)
Peter