I do big shopping once a month for non-perishables that don't go on sale (bulk organic beans), then buy weekly at the farmers market and grocery story for dairy. When something is on sale, I stock up. I buy ahead on pasta, for example, since it usually goes on sale about every six weeks. So my actual grocery costs are less than the ones shown in Wildly Affordable Organic because I don't want to assume anyone has the funds to buy ahead.