So I suggest you check to see if you have any offers to redeem. I'm not quite sure if this is a one day deal or today just happens to be the start of this offer.
Here is what you will need to do to check:
- Make sure you’re connected to the same network as your Chromecast.
- Open the Chromecast iOS/Android app
- Tap your device, then find the “Check For Offers” button (it should be hiding behind the three-dot button in the upper-right)
- Confirm your Chromecast serial number with Google