A few nice coupon images I found:
Image by sinosplice
Nowadays the "coupon" is to look up a page online (like this Dianping page) and show it to the waiter with your smartphone.
Image by K?
Image by emotionaltoothpaste
I used to make IOU coupons for my mom and dad as gifts for Mother’s Day and Father’s Day and the like. Apparently, there was quite a brainstorming session involved in drafting up those bad boys.