Target will take a store coupon and a manufacturer coupon for the same item, which can help make it cheaper than your local grocery store or Wal-Mart. My grocery store will do this too.
You can find Target coupons on their website, or sometimes they randomly mail out booklets to people in the mail. There's no real rhyme or reason to who gets the store coupons.
I've also found that I'm able to get a lot of my toiletries at Walgreens for really cheap because you can use the coupons in their ads and stack manufacturer coupons there too. I don't have a lot of time to line up these deals but the people on sites like
www.hotcouponworld.com and
www.slickdeals.net are able to find those deals. They also have threads dedicated to lots of grocery stores on HCW. There's no cost for either site.
If I had a family, I'd probably be all about buying in bulk, especially since I could practically walk to Cost-Co, but I'd never get everything used in time, nor do I have the space.