Amex currently has an offer of $20 off $50 on Boxed. plus you can use a referral code (works like a coupon) for $15 off. They sell food, plastic items, stamps, some gift cards. My code for $15 off is KO6QH

Yes, they have increased it to give $15, get $15.

There are also codes for 25% off - survey10, survey20 and survey25. You have to use $15 referral code on the first order and other coupons later because $15 is only good on the first order