Thinking about picking up a Nexus 7? You might want to get on that before the end of this month (right here), as the $25 Play Store credit promotion Google announced with its slate at Google I/O expires on September 30th. That means you must redeem the promotion before that date by signing into your Nexus 7 with a Google Wallet-linked Google account (that has a credit or debit card on file). Here are the terms indicating as such, emphasis ours:
2. In order to receive this promotional balance for the tablet activation, you must currently have or create a Google Wallet account on your tablet, and you must also add a credit card or debit card to such account (or already have a credit card or debit card in such account) for use in future purchase and payment transactions with the Google Wallet, by September 30, 2012.