Has it really been two years already? You're getting to be such a grown up app marketplace, Google Play. Google is offering some modest sales to celebrate two years of Google Play (also two years since the Android Market was smothered in its sleep). You'll find an assortment of apps, music, books, and movies, but don't expect amazing deals.
Most of the apps are offering discounts on in-app purchases. Although, you can play as a bugdroid in Badlands now, which it worthy of celebration all by itself.