You can save a HUGE amount of money using coupons if you have the time and energy to devote to it. Most people don't.
If you only clip coupons for products that you regularly use and you go through them AFTER you make a shopping list, then your savings are 100%.
The danger is in buying items you don't really need or use because they're 'a bargain'. If you pay attention to what's in your pantry and what's on sale, you can save even more by combining sales with coupons. There are stores that double coupons for even