Google announced that it would be adding 4K streaming support to YouTube TV at the beginning of the week. Google TV is now trying to get YouTube TV subscribers to sign-up for its $20 monthly add-on. The promotion includes a free Chromecast and Google TV.Droid Life discovered the offer from a YouTube TV subscriber in a forum posting. In an email sent to customers, the company stated that it wanted to give away a Chromecast with Google TV to ensure YouTube TV subscribers have a great viewing experience.To take advantage of this promo, visit the Google Store to buy the streaming device for free. The code is not valid for the white model, as supplies are limited. In the emails fine print, it states that only US residents with an active YouTube TV subscription will be eligible. You will also need to have paid at least one Google payment. You will need to redeem the email if you find it in your inbox before the end the month. The code cannot be transferred if you already have a Chromecast with Google TV.