We are lucky to have a unique costume, magic, and party supply store like this in Champaign. I would imagine there is nothing else like it in downstate Illinois.
Understandably, they have a zero return policy on much of their inventory--imagine how many folks would try to return their Freddy Krueger masks the day after Halloween--you couldn't stay in business that way.
Just go in and be awed by the vast selection of oddities and novelties on display, you won't be disappointed.