Macia is right. I've used the vinyl from a friend's sign company for
years. They have a lot of waste--background and end rolls from the
brightly colored film they cut vinyl letters from. I've used it for many
design projects with high school students. A favorite is called "shapes
at war." Two students work together to design a battle field in which one
army of simple shapes takes over another one. They have to come up with a
way of having their shape gobble up the opposing side. You can use
scissors or x-acto knives to cut the shapes. I make them trace about 20 of
their shape designs from a template and cut them out before working with
their partner to design the battle.
The Surgeon's Motto: "Never say 'oops!', always say 'there!'