I upgraded my Misa costume. I already owned the plaid skirt, bought the corset for $15 on eBay, got the shirt at a thrift store, the tie at Hot Topic, and I re-used the boots and stockings from my other Misa costume. I was going to wear a blond wig but my friends convinced me at the last minute to use my real hair.
Not a costume award...but my friends and I did a skit at Nekocon and won the judge's choice award. We got a lot of laughs with our skit :) It's on Youtube: http://www.youtube.com/watch?v=uzWB_45UYt4