Go to Amazon Prime Gaming
Log in to your Amazon Prime account (if not already logged in)
Click the "Claim now" box
Click the "Claim code" button on the window that appears
Click "Copy" to copy your unique promo code
Visit the Pokemon Go website
to redeem your code
Optional: Android users may instead redeem their code in the Pokemon GO app by accessing the shop menu and scrolling down to the promo code entry field.