I have always loved shrinky dinks and hated the prices. I finally figured out what to use to DIY them. Several blogs said that bakery containers were the right type of plastic. The ones at walmart are NOT. Walmart uses plastic with the recycle #1 and for shrinky dinks you need #6. #6 is polystyrene, which is used for cd containers, which seem rather thick, and plastic silverware. So I looked at the various plastic disposable plates. The plastic solo plates are #6 and so are the chinet clear plates. You have to be careful cutting the chinet, but they work. I haven't tried the solo ones yet. I paid $2.82 for 8 chinet plates that are 10" in diameter. Shrinky dink plastic was 2 sheets smaller than a piece of notebook paper for $5. I also got new sharpies (ALWAYS happy to have new sharpies, rather an obsession of mine, lol!) as mine have all run away with my children. It still was a better deal than buying shrinky dinks. I put them on a piece of foil on a cookie sheet in a 350-400 degree oven and watched them until they wrinkled up and then just as they were all straightened out I took them out. If you want an ornament or button, be sure to put a hole in them with hole punch before baking. If you forget, use a hot ice pick or nail and carefully smooth the edges with a hot nail or with an emery board.