go to ebay and search for airbrushes ... you can get them for about $20 - nice double action, with gravity cup.
buy several.
easy to use and maintain
since they are cheap, you can basically go through about 10 before you reach the cost of Pasche or Badger airbrushes.
as to learning how to use - search youtube for airbrush tutorials take what they say as a guide.
site down with an old model or sheets of paper and just spray some paint.
go back to the tutorials and rewatch ...
as for compressors ... well, i've had a Pasche compressor for 15+ years now, i'd say spend the money here, this cost me $250 at the time.
A tank is a must if you want to get serious ... get a full rig, might cost $400 but it is worth it ...
definately a moisture trap with regulator - don't skimp ...