I'm just going to rattle off things we buy reguarly as a family from Sams...
TP, diapers, meds (over the counter and perscription) , shampoo and soap, fozen foods in bulk is a great price, soda , syrup, cereal, mac and cheese, blocks of cheese, laundry stuff , printer paper, wine, muffins for breakfast, cakes/cookie cakes for special family events (their cookie cakes are amazing!), they always have lots of clothing for me and my kids at a really good price, my daughter eats a ton on strawberries so we buy those there, if you're a chip family its a great place to buy those, oh and how could I forget kerrygold butter (love that stuff!).
I could go on but I think you get the point.