Is this for home gaming? You could probably make a simple mech with a set of rollers that sucked up anything you put in, then trip a photosensor when it goes by, and dump out coins. I don't know why you would need this for home gaming though... I understand the desire to have a pocket full of actual tokens to put in the games, but I never got much of a kick out of getting change. Maybe check ebay to see if they have any used ones.
Good Luck