Coupon creator - printable coupon plugin suggestion

[maxo]

For regional sites wanting to offer free or paid promos for local businesses...it might be cool if there were a plugin that let users create coupons that could be printed. Essentially, if plugin were enabled, it would add an "add coupon" form to the listing. Coupon form would have a title box, description box, expiration date, etc. The coupon then shows up/embedded in the item listing description area.

Good idea or bad idea?