Amazon and American Express are running another joint promotion where select American Express cardholders will receive 20% off of Amazon purchases when they use any amount of their AmEx reward points during checkout. It seems like very few people qualify for this promotion. To see if you qualify, simply click here. If you see the offer details, then you qualify. Otherwise, you’ll see a message saying that you are not eligible. If you’re among the lucky few who can get in on this deal, you don’t need to pay for your entire order using American Express reward points to receive 20% off. Those of you with American Express cards that don’t qualify might be interested in the other AmEx promo that earns you 3 months of Prime membership for free.