As you know, this is not the first time Google offered Play Store credit to Chromecast owners. In December 2014, Best Buy & Amazon.com have offered the $20 Play Store credit (as voucher via email) when customer purchase a new Google Chromecast which selling at price $29.99.
And today, this is another gift from Google as a part of their Valentine’s Day celebration, you will have a change to get $6 in your Play Store account if you own a Chromecast. This credit can be used to buy anything in the Google Play Store like games, apps, music, movies, books and more.
All you need to do is just head the link below, verify the device and click redeem. Make sure you are connected to the same network as your Chromecast.