Lowes and Home Depot carry the plexiglas and acrylic sheets. I don't know about the craft stores. Anyway, they can be cut into any shape. The acrylic sheets are the best and can be marked using a permanent marker. I would recommend a very fine point. It will be permanent. My cousin will cut me any shape on his band saw. I have a scroll saw but I have not tried it. Some picture frames come with plastic instead of glass. I did not check the hardware stores yet. Good luck!