About $800 a month during the winter. Much less in the warmer weather when we eat a lot of our garden produce. We can cut that down when we need to, but right now we are enjoying a huge amount of produce. We eat a small amount of meat, a gallon of milk a week and some cheese. The rest is grains/nuts/seeds bought in bulk and lots of veggies and fruit.
ETA -- there are 2 adults, 3 children and one nursing baby.