Maybe the code was limited to so many uses before it expired or it was glitched(like the last code that was taking money off of the Move/Sports Champions bundle) and now they 'fixed it'.
It's back in stock, but it's saying the code isn't valid. WTF!?
EDIT: I just tried the code with the Move bundle using both CAPS and lower case for the word SAVE and it said it was an invalid code both times.