Sources for Plastic Drink Rings?

My daughters special ed class used to do these for fund raisers. I had never seen them before, but they must be easy to make as all the kids made them and they turned out really cute! They took orders for them as they were always running out of them at the Christmas bazaar.

Oops sorry, forgot the question, I'm not sure where my daughters class got their plastic from, but because they were a school, I think they got with the vending machine guys who came to fill the machines and got them from them as they filled with 6 packs. Try Pepsi or Coke and see what they say.