I would recommend (if you’re in the US) to check Wal-Mart for fabrics. They’re so cheap in the clearance area, around $1-1.50 per yard. The remnants section in any fabric store is also worth checking out. If you can’t sew, bust out that hot-glue gun, and “sew” a costume using the glue as a seam binder.

Going as a greek god or goddess is pretty easy; six yards of an interesting fabric draped like a toga (you can find direction online), and a fake ivy headdress…and you’re Athena!

If you don’t want to spend the money on a pattern for a costume, use clothes you already have, and take them apart at the seam–voila! a ready-made pattern.

If you can turn a bridesmaid’s dress gothic with a little black RIT dye and some white lace. On that note, you could also change the color of any wedding dress or otherwise light-colored dress with a packet of dye. Add some leather, brass ornaments or a pocket watch and you’re a steampunk.(Fake blood dripping down any dress is also pretty rad.)

If you’re a gent, dig out your black suit and tie, iron up a white collared shirt, wear a pair of sunglasses, make a fake ear bud with a curly telephone cord that goes from your collar to your ear, and go as a member of the MI6, CIA, or the Secret Service. Be sure to have proper identification you can flip out at any moment.

Last, check craiglist.com for cheap costumes other people are selling or trading in your area. You may even be able to sell your old stuff. I got a $50 wig for $10, and it’s beautiful.