Google had been, and still is, running a promotional offer for those who purchase a Nexus 7 tablet. Though, that still is portion will be changing at the end of the month. Just to recap, if you purchase the tablet you will get a $25 credit that can be used for Google Play purchases. And well, as to that changing soon part — that offer will be expiring on September 30th. To clarify, September 30, 2012 — the end of this month. As for those who have already made the purchase and who have already claimed their credit. In this case your credit still has an expiration date, however you have another year to use that up. Once you claim your credit you will have until September 30, 2013 to use (or lose) the balance.