whats an average price for a nice paint job

Assuming you are talking about a solid color (no graphics) repaint...you're probably looking at around 2grand. I had a miata painted about a year ago and it was 1800, so I would assume a supra would be a little more due to size. Just depends on where you go though. Make sure you pick a reputable shop. The one I got mine painted at, offered a lifetime warranty, and they've been around for a while so I trusted them. They did such a good job in fact that the paint was way shinier than any brand new car. You can get it done cheaper at some places but it's not gonna weather as well as a quality job.

nice street paint job or a real show quality paint job?
I wouldn't touch a MKIV for less than $5k,show quality job will cost around $10k includes pulling motor,all the lines, hardware in engine bay, all glass removed as well as every clip out of the body
Stefan