While I agree that cans can be kept pressurized by heating them, I still don't care for them. They just don't last long enough. I have a small compressor which I use frequently, but I also have a portable air tank from Midwest Products with a regulator. It holds up to 125 psi, and lasts through quite a few sessions. A big plus is that it's quiet. Just fill it up and the local Stop and Rob once in a while. The whole setup was probably no more than $75.00, but I think it was way less. Either way, with a compressor or air tank, you need a moisture trap. Here in Texas, even that doesn't work all of the time due to the high humidity. Nothing sucks worse than having your airbrush spit water into a a laquer or enamel paint job.
The ultimate solution is to get a CO2 bottle with a regulator. I have a small portable one. It's quiet, moisture free, and last quite a while. It is a little more costly though, in the long run.
As for my airbrush, I've been using the same Paasche single action since 1983. It beats the hell out of my first rig-one of those cheapo $10.00 airbrushes, which I ran off of a spare tire.