Now, just before the Christmas, Google has announced another such offer for its HDMI media streamer. If you buy the Chromecast between today and December 21, you will be eligible for $20 of credit in Google Play Movies. You might also be eligible for the offer if you purchased your Chromecast yesterday (i.e 7th December).
— Google Chrome (@googlechrome) December 8, 2014 Even though Google says otherwise, it looks like it is possible to use the $20 credit on the Play Store for purchasing apps and games as well. Google is already offering 2 months of Hulu Plus subscription free with the Chromecast, along with 90-days of Play Music All Access subscription.