We keep our grocery bill very low by buying in bulk from Costco. As soccerluvof4 said, we do check the price per ounce/unit very carefully, because not everything is a deal. We typically go to Costco once a month and stock up on: garbanzo beans, lentils, quinoa, oats, dried fruit, rice, and frozen salmon, plus household supplies (dog food, toilet paper, toothpaste, etc). Then, I go to the grocery store about once a week for just fresh fruit and veggies. Similar to MoneyCat, I haven't found it worthwhile to buy perishables at Costco because it goes bad before we (2 adults) can eat it all. We focus on not wasting any food, which is much easier to attain by buying the perishables in small quantities each week.