My wife is a coupon fiend! She has one of those accordion folders filled with coupons, and she brings it everywhere. She's been known to use multiple coupons on the same item to get it for free or money back! And don't even get her started on rebates. For those, she has a three-ring binder with all the different rebates she's applied for.
To date, her biggest coup was getting boxes and boxes of free Cheerios. For a limited time, Cheerios was advertising "Free box of Cheerios" on every box. It involved buying a box of Cheerios, getting the "code" from the inside of the box, going to the Cheerios website, entering the code, printing out the rebate form, mailing it in with the receipt, then waiting for the rebate check. She tested the waters to see how many she could get, and, apparently the offer was unlimited. We literally have stacks of Cheerios all over the house (probably nearly a hundred...I'm not kidding). And considering we have two little kids...we're going to need every single box we can get.
Coupons and rebates rule!