My wife is a big coupon shopper for groceries. She typically saves 60-75% when she shops, and she's upset if she doesn't save 50%. Like others have mentioned it's a little work intensive, I think the first couple of weeks are the most work while you're building up your coupon stockpile and getting them organized, after that it takes less effort to just maintain your selection. I think my wife maybe spends an hour a week while we're watching tv getting her coupons in order. She's not very hardcore about it compared to some, her employee who showed her how is crazy with it and often gets credit from using coupons worth more than items costs to pay for meat- sometimes she ends up leaving with gift cards and not spending any out of pocket. My wife tried some of those methods and didn't feel right about it, but the system can be worked.
You also don't necessarily get what you want right now because the general rule is to not buy an item if you can't pair a coupon with a sale. We're no longer the "plan the meal then shop for ingredients" folks but rather "what can we make out of this stuff?" people.