Drittz 
Amazon offers Select American Express Membership Rewards Cardholders: 20% Off Your Purchase when you use at least 1 Membership Rewards Point and follow the steps below.
Steps
Click here to link your American Express Membership Rewards account to your Amazon account
Click to Activate the promotion and find out if you are eligible
Add products sold and shipped by Amazon.com to your shopping cart
Proceed to checkout and select your American Express Rewards Card as your payment method
Select the amount of Membership Rewards Points you would like to use for the purchase (must use at least 1 MR point)
The 20% Off discount will automatically apply to qualifying items (this promotion can be redeemed on multiple purchases with a max discount of $50)
