I divided up my grocery list into four broad categories: dairy, meat, produce, and dry goods. I chose identical products at the lowest price (i.e. if there were onions and organic onions, I chose the non-organic). If the product was only sold at scale (everything sold at Costco), I put the full amount and price you’d have to pay in parentheses. If I couldn’t find an item (why doesn’t Costco sell sweet potatoes?), I left it blank.