You do have to pay a membership fee; however, it pays for itself when you save on bulk items. The secret is to go with a list and stick to it. Milk, eggs, cereal, peanut & almond butter, and other every day grocery items are cheaper to buy in bulk at Costco than at any grocery store. However, produce is often more expensive.
The service at the check out counters is always good; however, it is sometimes difficult to find products in the store as there is no signage.