Perhaps you've received one after making a purchase at Banana Republic. That extra receipt with a url and the promise of 20% off your next purchase for answering a few questions about your visit to the store. Gap does them, too, as part of the same corporate monster.

The survey takes a good five to ten minutes, and you have to actually think about the service you received. But you get a discount code good for one full price item which must be used within three months.

Too bad it doesn't come with an alarm, or glowing red light to remind you to a) bring it with you when you go shopping or b) pull it out of your wallet where it's been folded for two months and 28 days. After all, the discount is only worthwhile if you use it!