There is a book titled "Prison Money" that was written several years ago (more than ten) by a former very close friend of mine who has since passed away. His name was Jerry Zara from Point Pleasant, NJ. Jerry would exhibit his Prison Money collection around the country. He had a store manequin dressed up in a black & white striped inmate uniform with an authentic ball and chain clasped to the ankle set up along side of his very interesting display. It was a real attention getter. Prison made zip guns and all. I recall one item that Jerry referred to as a "bronzine". It was a metal token that prisoners received for donating blood. The token was good for purchases at the prison commisary. I'm sure that plastic chips were used in card games.... maybe by prison guards as well. It's very common that cigarettes were used as wagers in prison games. Yes, there are folks who collect this material. It was quite popular for awhile.