Update: This highly popular deal is still available.
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.
StepsClick here to link your American Express Membership Rewards account to your Amazon accountNote, you often have to wait 24 to 48 hours after linking your rewards account before you can "activate" the offer. Check the link in the next step after a few days for eligibility.
Click here to activate the promotion on your Amazon accountAdd products sold and shipped by Amazon.com to your shopping cartProceed to checkout and select your American Express Rewards Card as your payment methodSelect 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 (max discount of $20)