Yeah, seriously. Con's are supposed to be fun, even if you can't dress up. Besides, there's always a cosplay you can do, even if it's not the character you'd probably be thinking of.
(try going through your closet and look at your clothes, and try thinking of characters that wear clothes like that. I mean, seriously...that's what we did for my sis's Kyohei costume, and all we had to do was buy shoes.)