Get some local fuck boy who does stickers and buy a roll of this.
http://www.ebay.com/itm/24-X-10yd-Wh...cAAOSwPc9W0-BQ
Make some shit in photoshop, throw into printing program. Do half of the height for one section being its only 2 feet wide and then print out the other half. Cut out whatever of the white background you dont want and just lay it on the car. Some local wrapping place will charge an arm and leg for anything custom down here. Probably just as much as a normal paint job if you want some loli on the side of your car.