So, just $5 per day each. That’s $2 less per person per day than the average USDA food budget. For a family of 4 that is $600 per month, with some families coming in a lot lower.The average USDA monthly food budget for that same family is $840. found a few thrifty’s, a lot of low-cost or moderates, and no one who admits to spending the liberal plan :-). So for the sake of argument I’ll assume that the moderate plan is pretty average. The moderate plan for a family of four with small children is $855 per month. That is $7 a day for each person.