Amazon Music Unlimited offers a digital catalog with millions of songs ad-free and on-demand with unlimited skips, offline listening and new releases from today's most popular artists.
If you wish to keep Music Unlimited after your three month trial ends, your membership will auto-renew at the standard rate of $7.99/mo. (discounted rate for Prime members) or $9.99/mo. (non-Prime member rate) unless cancelled.
You may cancel at anytime after signing up (manage subscription here) and once your three month trial ends, your access to Music Unlimited will discontinue and you will not be charged.