Cancel your Amazon Prime account
To cancel your Amazon Prime account, simply log in to your account. Hover your computer mouse over the Your Account tab at the top right side of the page. Click on the Your Account button from the drop down menu. Scroll down the page to the Settings and click on Manage Prime Membership. Click on the button that reads Do Not Upgrade or Do Not Renew. You will not be charged the fee for the following year.
Customers can also visit the Amazon Prime Help Page here: http://www.amazon.com/gp/help/customer/display.html?nodeId=13819211 to find alternative ways to cancel service.