Super Girl Costume (from Halloween 2007)!
(We're focusing on the girl on the left - the other two are store-bought costumes, but in the spirit of thriftiness, the lion costume came from a consignment store and the monkey costume was borrowed from my SIL).
For this costume we, again, visited the local Good Will store to find the blue shirt, denim skirt, and red cape which was not actually a cape, just a large piece of red fabric tied around her neck. The black boots are hers, and we bought the red tights from Kmart or something (the down side to thrift stores is, they only have what they have, and sometimes you just can't find or make what you need).
Anyway, this costume was SO easy to put together, as you can see, it's just regular clothes in the right colors to make Super Girl. For the S symbol on the front of her shirt I bought two pieces of tag board, one red and one yellow, and made it myself. And, there you have it! Easy, thrifty, homemade Super Girl costume. Awesome.