Total cost: $13 for two capes
(not including thread, but seriously, can you beat that?)
To make these capes, I followed the directions on Puking Pastilles' tutorial but I decided to use machine-washable, wrinkle-resistant satin so it would hang nicely (found it at Hobby Lobby for $2.99 per yard). I did the Batman and Superman logos free-hand, and the letters had to be the boys' own initials instead of the generic Superman "S."
Why should girls have all the dress-up fun?