[quote name='MikeHoncho']I don't think there is but I might be wrong. I think the free shipping might work though.[/quote]
Nope, just tried it to make sure and received a message that this code is not valid with the purchase(tried a used 360 to make sure it was over the $50 mark).
OP, if you're looking for a price cheaper than Gamestop on a system, look around on game trading sites. Usually you can find someone selling a system at $20-$30(if it's current gen) less than GS, just so they don't get ripped off at GS and can get rid of it ASAP.