Store-bought Halloween costumes can cost a small fortune, especially considering they're usually only worn once. Find out how to save big this year using these tips.Make your own. Browse Pinterest for a plethora of DIY costume ideas. You can usually find the costume elements you need in your house or purchase them cheaply online. Swap costumes. Ask a friend who's roughly your size to swap last year's costume with you. If you have kids, think about bringing up the idea with other parents at your child's school. Visit thrift stores. You might be able to find a full costume or elements you need for a DIY costume at thrift stores like Goodwill. It's an easy and cheap way to assemble a costume. Reuse clothes you have. You might be surprised at all of the different costumes you can make using clothes you already have in your closet. If you have a flannel shirt and overalls, you can be a farmer. If you have a denim shirt and a bandana, you can be Rosie the Riveter. If you have a striped t-shirt, you can pair it with a black hat and dress up as a bank robber or use the same shirt and go as Waldo. The possibilities are endless! Shop end of the season sales. This might not help you out this year, but take it into consideration for next Halloween. Shop the end of the season sales starting on November 1st and buy a discounted costume you can wear next year.