Where do you buy these and are there certain sizes/thicknesses that work best for making the chocolate cigars?

I wondered the same thing. Am an artist and had a tablet of acetate sheets in my studio that I had purchased in the art supply department of HobbyLobby. Just used a little craft paper cutter to cut them and they're really easy to make. Only made a few to see how they would work and they came out just like the pics. Haven't made a cake with them yet as I'm wondering how to attach. Art they stuck onto wet buttercream or to royal icing?