I've been a member of Sam's for over 15 years, and I like it, for the most part. I know I've saved a ton of money, but then I'm not buying just for myself either. I've bought everything from jewelry to toilet paper, and everything in between. The biggest savings is on their meats and frozen goods I think. I buy the big packs of meat and then break them down to whatever size I want, and freeze them. I can buy two big chickens in a pack for less than I would spend for one in the grocery store. You can buy the smaller cans like tuna, but they're in packs of 8 so you might not want to buy that much. Peanut butter is a bigger jar than you would get at your regular grocery, and they're usually packed in 2's. You do have to watch prices tho, since I've found that some things are cheaper at Walmart, and at Walmart, you have more off brand labels to choose from which are going to be cheaper too. I get my prescriptions filled there too - usually a lot less than Rite Aide or Walgreens.
All in all, I've been satisfied with them, and I have saved big bucks over the years.