You probably think that coupons save you money, and if you use them correctly, you're right.
However, stores and manufacturers issue coupons to increase their total sales, which means that if you aren't careful, you can end up overspending when you shop with coupons. Coupons expose consumers to additional advertising, increase shopping activity, steer consumers toward more expensive products and provide temptation to buy discretionary items.
To make sure that you really are saving money when you shop with coupons, read my Financial Edge article for Investopedia, 6 Tricks to Make Coupons Work for You.
And for background on this topic, read 6 Sneaky Ways Coupons Make You Spend More.