So, I found a video on the internet which should have bargain-hunters, cheapskates, and economists (to be redundant) foaming at the mouth. By using coupons and mail-in rebates, a woman was able to cut her grocery shopping bill down from over $150.00 to just $9.43. Find the video here. So why isn't everyone saving 97% on their shopping, and putting the grocery stores out of business?
The reason most people don't do this (and never will) is because it's inefficient. Yes, it's very impressive to see someone save ~$145 off their groceries, but the real question is how much time did it take, in coupon saving, organization, and so on, in order to accomplish that? The woman in the video said she collects coupons, sends in rebates, and plans all her shopping in advance... If it took her 14 hours, she effectively earned $10/hour for her coupon-clipping work. However, I'm guessing it took longer than that, and her "wage" was actually much lower.
For people who have jobs, it'd be more effective to spend those extra hours working than clipping coupons. If you don't have a job or are paid a very low wage, coupon clipping could make sense. However, there are a variety of other ways to make money on the internet - filling out surveys, using ShortTask, or advertising on Twitter - to name just a few. For an hourly rate, you can almost certainly do better than coupons.
If you're a college student, spend that time studying instead -- you're going to school to make more money later, so focus on grades, not penny-ante coupons (unless you're studying english or sociology, in which case I suggest dropping out and coupon-clipping full time, because it'll be more profitable).
There's an efficient level of coupon saving, which depends on your income and how you value your time. For highly paid professionals, the efficient amount of coupons might be zero, while some others may gain a small benefit from spending their time that way. Taking coupons to an obsessive level, as this woman appears to have, is just wasting time for yourself and everyone in line behind you.