Halloween costumes can be pricy and many parents are no longer willing to foot the bill for their older teenage kids. Teens can make their own costumes by using grocery bags that they can get for free. By cutting a hole in the bottom of the bag for a head and cutting a hole in each side of the bag for arms, you can make any rectangular shaped outfit that you can imagine. You can also cut a line down the front side of the bag and make a vest. If you mess up, you can just grab another bag and start over again. Masks are even simpler to make. Just cut out holes in the bag for your eyes and decorate the outside of the bag with whatever other decorations you like. You can fasten a wig to the top of the bag mask or glue any other scary objects to the mask to achieve your desired effect.