Tint stickers for eyeglasses?

I want to take a pair of vintage safety goggles and make a variety of colored lenses for them. I've already harvested the lenses from some sunglasses and cut them to size. However, it was a real pain. I thought it might be easier to just take the clear lenses that came with the goggles and put some color tinted film over them. Unfortunately, finding said tint film is proving easier said than done. I thought about car window tint, but I don't want to buy an entire roll. Does anybody know where I could find what I'm looking for: a small sheet of transparent UV tint (with various available colors) that can be cut to size and stuck to a eyeglass lens like a decal?