i do it sometimes with things i know i'll use. but it's just too much darn WORK to buy up a bunch of stuff just because you have coupons. seriously, i tried it. oh my gosh, i was spending HOURS trying to match up sale prices with coupons and track which places would double or triple the coupons and would that actually come out cheaper than a store that sells it for cheaper but doesn't double the coupon... and so on.
what i discovered really quick is that the one thing i was stockpiling the most of was.... coupons. and can you imagine how many trees are being wasted every sunday when people buy up several newspapers and don't even look at anything but the coupons?
now i do have a friend in vegas who works at the food bank i used to work at. his wife is an extreme coupon-er. she gives away what she doesn't use, and frequently the food bank is the recipient of her donations... toiletries being the most common, because at the drugstores, that's what you usually end up paying nearly nothing for.
however, if there's a good coupon for something i use a lot of, i'll clip (or print if i find them online) as many as i can, and i'll wait for a sale to match it with. i have lots of cream of chicken/mushroom/celery soup, lots of tomatoes and tomato sauce, many boxes of tea bags, and probably a month's worth of toilet paper. but i can manage to squeeze in all my surplus in the area where it should be kept.