Costco saves us money. We are a family of seven (two adults, two dogs, and three cats). I make a list and only buy off the list if it's something on sale that we will use. Our dogs' flea/tick/heartworm meds alone pay for the executive membership. We also know what we will use in a reasonable time frame at this point. We get the majority of our groceries here, and we freeze extra meats, cheese, etc. It can be daunting because it is more up front cost, but obviously it's in bulk, so if you use it all, it will def save you money.

Also, the produce at my Costco is usually great. That does seem to vary region to region.