Capcom is currently running a sale on the PlayStation Network, with all the Street Fighter IV costumes currently half off, with the complete bundle available for $6.25. Additionally, these costumes will be forwardly compatible with Super Street Fighter IV.
Now, while the costumes are nice and usually include some sort of reference that fans should catch (such as Balrog dressing like Apollo Creed), at the end of the day, they’re nothing that actually changes the gameplay. Doesn’t mean I didn’t buy them all on the Xbox version of the game, being the huge Street Fighter fan that I am.
The costume sale is running until the end of March.