I’m betting that it’s one of those internet, fake coupons, like “Get $25 off a $25 purchase at Wal-Mart”, or “$90 off a $100 purchase at Kroger”.
I bet you are right...
My son worked for D&D for a while..
They probably had a dozen times fake faceboob coupons hit the store...
Finally they put up a copy of it on the door with “Fake Coupon” on it...
They still had people claim it was real...