When I teach coupon classes, one of the audience's favorite lessons are what I call the "best-kept secrets" of couponing. These are the secrets that help push your savings potential to the maximum! Today I'll share with you one of the best and most exciting ways to get groceries and other products for free. (And isn't that what we all want? Who doesn't love free stuff?)

Secret #1: Coupons for "One Free Item"

You may be surprised how many coupons for free products exist! You can regularly find coupons for free items in newspaper inserts, on the Internet or even in the stores you regularly shop. These are some of the easiest and most fun coupons to use! Recently, our newspaper inserts had coupons for one free loaf of a brand-name bread, a free single-serving beverage and a free air freshener. There's nothing better than getting something for free with little or no effort.

Or is there? You may be surprised to learn that running right to the store with a coupon for a free item isn't necessarily the best way to use these types of coupons. When I get one of these coupons I file it away and then I watch the sales. If my store features this item in a "Buy One, Get One Free" (BOGO) sale, that's when I redeem the coupon for the free item... because I will then get two of that item for free instead of one!

Why does this work? I'll give you an example. I have a coupon for a free bag of frozen vegetables. The coupon states that it has a value of up to $1.99, which is what the store will receive when they redeem the coupon. That's also the normal price of the vegetables. But when the store puts the vegetables on sale BOGO, they're selling two bags for $1.99. If I walk in and buy two bags and pay cash, I'll pay $1.99 and get two, right? The same thing happens when I use my coupon for one free bag of vegetables. The coupon covers the $1.99 cost of the first bag, and the second bag is free.

This is all part of playing the coupon game. Getting one item for free is good, but getting two items for free is even better! Now, if my coupon gets close to the expiration date, of course I will redeem it and get my free product. But it often pays to play the waiting game, as the BOGO sales will play out in your favor more often than not.

Over the course of the past few months, I kept track of the coupons for free items that I accumulated: 38 in all. I held all of them and watched closely, matching them to BOGO sales over that time period. During that time frame, 31 of the items went on sale BOGO. By playing the waiting game, I was able to get 62 free items with those 31 coupons! And with the remaining seven coupons, of course, I still got those seven items for free, too.

This truly is the best way to use coupons for one free item. You're getting two... for the price of none! Next week I'll share another best-kept coupon secret with you.

Jill Cataldo writes from suburban Chicago on coupon matters. Her column and some valuable local coupons appear in Thursday editions of The Daily Astorian.

Readers are advised to check with their favorite store's customer service counter to learn its coupon policy in case it varies from Cataldo's suggestions. Some regional differences and rules do apply on doubling, overage and other issues.