This article has some good tips for using coupons though the internet.  Spending the time to find the deals can save you big $ in the end.  The key to coupons is two fold.  You first have to ask yourself, "would I buy this product if there was not a coupon?".  Secondly, you have to make sure that the sale price on a branded product is not more than a regular price on a store brand product.  For exaple, I go to Costco and they have $3 off Huggies diapers all the time in their coupon book. When you look at the price of the Kirkland brand diapers (even with the the coupon discount) it is still cheaper to go with the Kirkland. 

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