Learn to create your own vinyl decals for cars

First think about the design of the decal. You can either print it from the computer or draw it yourself. To have design sturdiness you can attach the design to a poster board.
With a pair of scissors or a craft knife cut the design off the board. Be careful not to scratch you working surface.
Take a vinyl decal paper and put it faced down on a flat surface. Then put your design over it. Glue it with some tape and then draw the design on the vinyl paper.
Keep the poster board after you take it off for possible future use.
Now cut through the paper following the design.
Again take a piece of clear vinyl paper and place it with the back facing up on a flat surface. Take off the backing.
Now be careful while you are placing your vinyl paper cut with the design over the adhesive part of the new paper, making sure that the color part is facing down. Be careful about air bubbles and ridges. Lift the design a little and put it again when that happens.
Take off the backing from the paper with the design. The backing you removed from the clear vinyl paper and cover the complete vinyl decal with it. You now have a homemade ready to use vinyl decal.