My wife helped me cut the jacket to fit and paint stripes on the suit; she also made the bat bow tie out of wire and papier-mache. For her costume, she salvaged fabric from Goodwill (several XL men's polo shirts in various terrible colors) which she cut up and stitched together by hand with black yarn. I helped paint the swirls.
Overall, I think they turned out pretty awesome. We got a lot of compliments and a few excited kids, so I was happy. Now I just have to think of something for next year!