Saying "every family is different" sounds extremely cliché, but it's true. There's no rule book or set of guidelines to follow. It all depends on your habits and your family members.
That's why when things come out about what a "typical" family or "normal" family does, people take offense. Who is this family we're all trying to model ourselves after, and what if mine is nothing like theirs?
Growing Slower posted an image using stats from the USDA regarding the cost of food. The website posted a chart of "monthly grocery budgets" for thrifty families.
Facebook page The Real Deal Of Parenting re-posted the image and it's garnered a lot of attention.