If you are interested in trying out Amazon Music Unlimited, you can get a 30-day through July 31, 2017. Not only that, Amazon is giving out an additional incentive for signing up for the free trial. Once your 30-day free trial is over, you’ll receive a $10 credit which you can then use towards any Amazon Music Unlimited Plan.
You can sign up for a free trial here and make sure to apply the code SUMMERMUSIC. If you decide you want to keep the subscription and pay for it, it costs $7.99/month or $79/year (for Prime members, non-Prime members is $9.99/month).