If you know a framer, you can get most of your acrylic for free. Framers regularly throw out long strips of acrylic when they are making new frames. They also throw out large pieces of acrylic when they are refurbishing old frames. Even if the old acrylic is scratched, it will work well in the oven, because the scratches go away when heated. Almost all of the acrylic that I have was free and would have otherwise ended up in the dumpster—so go make friends with your local framer :)