Artist Trading Cards is a whole new world for your imagination. They have been around for centuries and have become more popular in the last few years. You make them up, then trade with other artists. No passing of money is involved, although I see lots of them for sale on Ebay, by more well know ATC artists. They have to be 2.5 by 3.5 inches and each should be an original. I am not sure what I think of the notion at this point in time.
Here are my only four so far.
Check out current artwork on my website at http://www.dianakingsley.net