Cat litter, detergent, oxi-clean, movies, books, electronics, etc are all available and usually for better prices than elsewhere. I bought the case for my iPad at Sam's that was $50 there and $89 everywhere else. About 8 years ago, I bought a returned television for $50, had it repaired under warranty and it works like a charm still.
We alternate meat purchases every week or two. Chicken breasts $2/lb, in a 5 lb pack, pork loin $2/lb in a 6-7 lb package, skirt steak <$5/lb, 90% lean ground beef $2.50/lb, all of which we portion and freeze what we don't use right away. Butter is 4lbs for $8 (lasts us 3-4 months). At my local store, it is $3-4 per lb. We go through three dozen eggs a week, with DS and DH eating eggs every day and I use them in cooking and boiled on salads. Cereal is much better priced than from the grocery store for the same brand. Also, snack items like Nutrigrain bars, granola bars, breakfast pastries, etc. We could not eat as well as we do without our memberships.