YouTube Red, the ad-free version of YouTube that also includes a subscription to Google Play Music at a price of $9.99 per month, can be had as a Google Cast (Chromecast) offer for just $0.99 for three months. At less than a dollar, I’d say signing up is probably worth the hassle if it gets you the next few months of ad-free YouTube streaming with a bonus of the Google Play Music collection on the side.
If you own a Cast-eligible device, you can check to see if the offer is available to you by hitting up the Google Cast Offers page, linked below. Once redirected, the site will check all of your devices to see if the YouTube Red can be yours. If it can be, the click of a “redeem” button followed by a short sign-up process over at YouTube should be all that is required.