I did the math on what we purchase in smaller amounts at regular grocery (Winco or Fred Meyer) and found that many items (when I meal plan! ) are much cheaper there for the quantity we use. Especially: Seafood (we eat a lot of Salmon), nuts/dried fruit, PB, fresh fruit, frozen veggies, plain Greek yogurt, cheddar cheese, some meat products (ground beef & chicken sausages for us), coffee, olive oil, and tuna. Also toilet paper, contact solution, & tissues. If you only focus on staples and avoid the “fun” things, it’s very cost effective. We spend $200/month at Costco, and then I’m able to spend only between $80-100/week for other consumables at other stores for a family of 3 for all meals (breakfast, lunch, dinner, and two snacks for school).