1. Visit Amazon Prime Video and search for movies and TV shows to rent or purchase. Select a movie or show to rent or purchase. 2. Select "More purchase options" on any purchasable movie or show. 3. Select "Redeem a gift or promotion code". 4. Enter your code and click “Apply”. Although the price on the button will not change, your credit will automatically be applied to your purchase. Note that it is applicable only if the value of the movie rental is not exceeding your available credit amount. Otherwise, you will have to pay the difference. 5. Click the "Buy" or "Rent" button. After your purchase, you can confirm credit was applied by checking your order confirmation, which will be sent to you by email.