It's happened to all of us. You see an advertisement for the best price on the perfect item only to get to the store and discover it's sold out. You call every other nearby location with no luck, and just as you're about to give up, the helpful manager suggests taking a rain check.
Rain checks are written assurances that guarantee a customer the sale price on an out-of-stock or sold-out item. Rain checks sound great, but no matter what the manager says, there's no guarantee that item will ever be restocked. The best deals are often for products that are being moved out to make way for newer models or different inventory, so if you take a rain check on a cute red lamp at a closeout price, the promised discount won't be honored for the almost identical maroon one made by the same company that comes in next week. Plus, you might wait weeks or months for a rain-checked item (and in so doing, pass up great deals at other stores) and still not get your product.
The takeaway: Rain checks don't guarantee anything, so if you find another deal in the meantime, take it!