Not sure if it would work at a store that sells Hallmark but isn't a Hallmark store. The first line at the top of the coupon says 'bring this to your favorite Hallmark Gold Crown Store. You could try? The worst they can say is no.
I used mine last night and it worked great! (at a Hallmark store) I also printed one out for a friend and she used it last night as well. Thanks again!