When your local store has a fantastic deal on something but when you get there, they've sold out, go to the Customer Service desk and ask for a Rain Check.
Even if you don't need the item immediately, get a rain check. Don't argue with me. Get the rain check. Don't be embarrassed. They write out tons of rain checks. It's their job. You're giving them job security. Get the dang rain check. Am I getting through to you? ;-)
Months from now, when you do need that item, that rain check serves as your own personal sale! You get that item for the previous sale price. Many rain checks specify how many you can get at that price. If they ask you, I recommend you tell them to write 10. You don't have to buy 10, it just allows you to buy up to that many at that price.
The rain check also gives you more time to find coupons to save even more money.
A bonus is when you can find a Store Coupon and a Manufacturer's Coupon. You can't use two of the same type of coupon on one item, but you can put a Store Coupon and a Manufacturer Coupon together. That's called coupon "stacking."
Now imagine a buy one get one free special with a store coupon and a manufacturer's coupon, and you may end up with a free item.