We've just switched to an almost completely vegetarian diet during the week and DS2 has recently toilet trained so our grocery bill has dropped dramatically. We used to average $300 a week (2 adults, 2 kids). We buy premium quality, only shop at Coles (can't be bothered going to more than one place) and I never look for specials or buy based on what's on special. We've dropped to about $200 a week since changing our diet. We meal plan and rarely buy anything that's not part of the weekly menu.