GameStop partners with digital competitor Valve, offers Steam codes in-store

I wonder what the margin is on these? GameStop must be making a decent amount which means Valve is paying to have people without credit or debit cards be able to use steam.

GameStop partners with digital competitor Valve, offers Steam codes in-store:
U.S. retailer GameStop today announced a partnership with behemoth developer Valve, that sees the latter's Steam Wallet initiative made available in GameStop stores. Valve unveiled its Steam Wallet payment system for its Steam digital download service in 2010, as a means for users to buy funds usable to purchase games from the online store. Today's announcement means that GameStop customers can now purchase physical Steam Cards nationwide, which provide codes to add funds to a ...