I don't really like purchasing expensive costumes. If you go to any Salvation Army or Goodwill and look through some ratty clothes, chances are that inspiration will hit you and you can come up with something. Another thing I do is dress up as obscure characters. No one ever knows who I am, but I don't really care if they do. 2 years ago, I brought out the metal.

I was Nathan Explosion from the awesome Adult Swim cartoon Metalocalypse. It was a very thrown together costume, but I made it work. Black shirt, long black hair, eye makeup, and done!

Save some money!