Understanding: what you eat, and what goes into what you eat; is on of the first steps to being sustainable. You will find that there are some foods that you will have to buy; other foods may need to be given up altogether. However, milk has always been a small homestead staple. I have dived into the costs and consumption of dairy.
Above is a chart; which is, a compilation of the average American's consumption of dairy products. I did graph two costs to be more realistic. Lower middle class, and higher middle class, prices of dairy are listed. Obviously, the pricing will change household to household. Also, food prices fluctuate.
The chart is public, so you can use it do your own calculations. Just click the chart to enlarge.
Linked Sources
The chart is public, so you can use it do your own calculations. Just click the chart to enlarge.
Linked Sources
http://time.com/2933396/american-butter/
http://www.eatwisconsincheese.com/dairy/milk/milk-facts