Who is eligible?
Any user who has not yet registered or linked their Amazon account on IMDb and has not used Amazon Music Unlimited in the last year is eligible for this promotion.
How to redeem:
New IMDb Users: Create an account
Existing IMDb Customers: Link your account here by following the login instructions and using the option to link your Amazon account
That's it! In the next 48 hours you should receive an email from Amazon Music confirming your 90 days of Amazon Music Unlimited for free!
I have used Music unlimited Free trial before and I was still qualified for this offer.