Someone at McDonald's today had a fascinating understanding of how coupons work - she looked at the expiry date, rang in my discounted food, and then she gave the coupon back to me, because it hadn't expired yet. I couldn't let her do that and told her that that coupons typically are a one-shot deal; the expiry date just means that you missed your chance to use it. But I didn't tell her that my order came out to less than I thought it was going to be. I was supposed to get a free drink and fries when I ordered a sandwich. At my table, I checked my receipt and sure enough, I got a free sandwich when I ordered a drink and fries! I wonder if she's on a mission to subvert Mickey D's? :-)