We budget for $300 a month -- so $75 a week -- for groceries, and I make sure we stick to that by taking the $$ out of the ATM every two weeks and keeping it in a grocery envelope. When we were paying using our debit cards, we consistently went over budget just by not being sure of how much we'd spent already.
We're in Connecticut, and the $75 a week, plus WIC checks, covers 2 adults, 1 baby, and 3 cats. We're vegetarian, mostly organic. WIC buys cheese, carrots, tuna, milk, eggs, peanut butter, juice, some beans, and cereal -- a lot of the staples. I have two veggie gardens in our backyard which provide a goodly amount of our veggies in the summer and fall (the $$ for seeds and supplies comes out of the grocery budget), and I get the rest of our fruits and veggies from farmers markets as much as I can. Once or twice a week we have friends over for a potluck dinner, which lets us all try new dishes and cuts the food budget for all of us a bit. I buy in bulk at Ocean State Job Lot or XPect Discounts when it makes sense, I shop sales, and I clip coupons from the Sunday paper -- that alone usually saves us $30-$40 from a $120 shopping trip. I try to buy local and in season produce because the quality is better and it's cheaper then.
I think some of our bigger savings come from not constantly buying cleaning products, personal products, disposable diapers, and wipes. We use baking soda and white vinegar to clean just about everything and buy those in bulk. We use baking soda, apple cider vinegar, tea tree, and Dr. Bronner's soap on our hair (and it's much healthier now than when I used shampoo!). I use Luna pads instead of disposable pads and tampons. I just started using hydrogen peroxide on my contacts instead of the standard (expensive!) cleaning solution, on the recommendation of my optometrist. We cloth diaper and use re-usable wipes. I make "butt spray" with water, extra virgin olive oil, and tea tree oil.
I usually have just enough left over from our grocery budget to allow for a reasonable meal out once a month plus a few decaf coffees or snacks on the road and maybe a magazine or two.
Sarah, mama to Qualia, 8.5 months (who just started cross-crawling!)