The Amazon Music Unlimited free trial is normally only 30 days long.
Brad's Deals Editor Michael,
First-time Amazon Music Unlimited subscribers can try the service for three months for free by signing up today at Amazon. This subscription normally costs $7.99 per month for Prime members and $9.99 per month for Amazon users without a Prime membership. Amazon Music Unlimited gives you access to unlimited ad-free music and podcast streaming on any device. You can also download songs onto mobile devices for offline playback. The normal monthly fee will apply after the three months are up, but you can cancel at any time. There is no sales tax.