Since 2007, I have been fortunate to be one of over 400 Art-o-mat contributing artists. The work I submit is primarily 3D photo trading card sets (shown below). In addition, I create original Instax Mini (Polaroid) photos fore vending.
From the Art-o-mat® website:
Art-o-mat® machines are retired cigarette vending machines that have been converted to vend art. There are over 100 active machines in various locations throughout the country.