What is a good size air compressor for air brushing?Any important tips you can give when purchasing a compressor?

I don't recommend any air compressors... I use a compressed CO2 tank from a welding supply shop. Cheap, doesn't require electricity and silent. All you need is a pressure regulator (which is cheap), and a moisture trap...

How long do these usually last?Where did yo get the regulator and moisture trap??Home Depot?

Depending on how much you use it, it can last a LONG time... and a recharge is like $25 or less. I've used one since June and it's still going strong... should last through the end of the year for me at the very least.

The other stuff you can get at the welding supply I'm sure...

You can use anything from a spare tire to the best compressor made..Personally i use my roofing nailer compressor w/an extractor inline(removes moisture) and regulator for pressure control..the compressor cost me about 225 and it came w/3 air nailers and a stapler to boot..You need enough CFMs to run the airbrush which isnt a lot for that little gun..Now if you're planning on spraying w/larger equipment like and HVLP sprayer you'll need a large tank and a bigger head..Like an 80 gallon reserve tank w/a 3-5 horse head minimum..

For most purposes of model and figure painting, you'll only need an output of 35 lbs. of pressure at most... I think I use between 25 and 30 lbs.