I share a Sams membership with my sister, so that makes it $20/year for each of us. They don't seem to mind that we live in different states (although we were together when we signed up) and have different last names.

I live alone, so I don't do a lot of Sams shopping, but I do find it great for some things. Many of these have already been mentioned: gasoline, bread, meat.
- String cheese sticks are a great price
- Quaker oatmeal (the single serving packages) if I don't have coupons or haven't stocked up on sales (although right now I've got enough Kroger brand to last me many months).
- Tollhouse chocolate chips for baking.
- Canned tuna - I like the albacore stuff and it's rare to find sales/coupons on that at least where I live.
- Books and sometimes DVDs - They often have great prices on just released stuff, especially paperback books. It's rare that I'm not willing to wait for the book to show up at the used book store, but on those occasions Sams has the best price.
- Honey - It's a huge bottle but it doesn't ever go bad and the unit price is great.
- Cat litter - I get the "store" brand. I haven't found a better priced scoopable litter that works well enough for my taste that I can stand the smell of (Tidy Cat is great and usually has good coupons but I can't do the smell of it).
- Baking soda - you have to buy huge quantities, but I use it for laundry and in the cats' litter box.
- Store brand tissue (Kleenex but not that brand) - I get a big box of boxes to suppliment the sales/coupon deals of the good ones. They're not as soft as the name brand ones, but they're cheaper and are fine for me unless I have a cold or major allergies.

Also, I'm a volunteer youth leader and before trips I usually buy a couple of boxes of snack items to share with the kids. Usually it's Fruit Roll Ups, Rice Krispie Treats and something like Starburst or Dum-Dums. Sometimes I can do better with coupons and sales, but not always in the quantities I want/need. And it's also great to have the card when the youth guy gets bogged down in something and needs someone to run to Sams to get food for a cookout or whatever.