It is very easy to make window tints and generic bumper stickers & license plates!
Just use a text (letter writing) program, play around with the text size and font-type, test print on regular paper, final print on adhesive address label paper, then cut out with an Exacto knife.
Check out a couple I did today for the fun of it:
They would turn out even cooler when I start playing around on Photo Shop.
Try it!!
John