A customer can cancel an Amazon Prime membership by visiting the Amazon website, logging into his Amazon account and navigating to the Help & Customer Service portal. Users can also cancel a free trial of Amazon Prime via the same portal.
First, visit Amazon.com, and log in. Next, click the Help button located at the center of the page. From there, click Go to Your Account. Under the heading Orders, click Manage Prime Membership. On the left side, click End Membership. Amazon then directs you to a screen that asks if you are sure you want to cancel your membership. At the bottom-right of the page, click End Membership.