For new customers only, Google offers a Google Play Music Unlimited and YouTube Red 4-Month Trial for free. That's a $40 savings and tied with our July mention as the best free trial period we've seen from Google Play Music. Google Play Music Unlimited allows you to access 35 million songs on-demand and ad-free and to download music to play offline. YouTube Red allows you to watch videos ad-free and save content for offline watching.
Be sure to cancel the service before the trial ends; otherwise, you'll incur a $9.99 monthly fee.