You can get a great deal on Halloween costumes from Diapers.com. They marked down many of the costumes plus you can take an extra 20% off with coupon code: 20More.
The costume above is priced at $19.99 and then the coupon code drops the price to $15.99. Plus shipping on Halloween costumes are free!
I have found the Diapers.com costumes to be better quality than ones I have found elsewhere.
Also my orders from Diapers.com usually arrive in about 2 days. If you have not purchased costumes yet, you might want to think about it! I was just in Target last night and the selection has really dwindled down!