Must watch one TV show or movie before you will get voucher! Can cancel trial before you get charged (£79.99 for the year) :) Can take up to 30 days for you to get voucher.
You can cancel online - so you go to Amazon homepage, hover over 'Hello XXXXXX Your Account' near top. In dropdown menu select 'Your Prime Membership' and select the relevant option on that page. You can even set it to not renew at end of trial.
Terms and conditions: Offer expires midnight Tuesday 19th August. 18+. New customers only. One free trial per customer per 12 month term. Paid subscription starts automatically after free trial unless cancelled. Not redeemable in conjunction with any other offer. Your Amazon.co.uk gift certificate will be applied automatically to your Amazon account and you will be notified by email at the email address registered on your Amazon.co.uk account within 30 days of starting your Prime or Prime Instant Video free trial and streaming your first TV show or movie. If you do not receive your voucher within 30 days of starting your free trial and streaming your first TV show or movie, please contact Amazon customer services. Amazon can only accept claims for non-delivery of vouchers for up to 60 days from the start of the customer’s free trial. Existing customers converting from one Amazon Instant Video membership to another Amazon Instant Video membership (i.e. Lovefilm By Post, Prime Instant Video or Prime) are not eligible for this offer.