YouTube Red [youtube.com]
is offering 3 months for free to new subscribers which also extends to their music service "Google Play Music" during the subscription time.
: Must be a first time subscriber to Youtube Red or Googleplay Music.
( I tested it on accounts that were on a trial in January but it didn't offer the free months, However, an account that had a trial even further back was eligible so YMMV
Upon completion of your 3-Month trial, the monthly rate will be $9.99.
You may cancel at any time before your trial end date and still receive the full 3-months of membership benefits without incurring further charges