Random Google Play Store users are getting 80% off a "top app or game" (not in the U.S. though)6
According to Google, this offer is limited to those in Great Britain, France, Germany and Russia. We would be surprised if U.S. Google Play Store visitors don't receive some similar discount for the holiday.
According to the information sent to the lucky few receiving the discount, besides being limited to certain countries, the discount was awarded "based on past purchase history." Additionally, it appears that different winners are receiving the 80% off coupon with different eligible apps in mind.