Download a .pdf of the Official USDA Food plan budgets. They itemize a thrifty, low cost, moderate, and liberal plan and see how you compare.

The chart shows that a family of 4 with 2 children between the ages of 6-11 the following weekly expenditures:

Thrifty: $112.80
Low Cost: $144.90
Moderate: $180.50
Liberal: $218.60

Or Monthly Totals:

Thrifty: $488.80
Low cost: $628.00
Moderate: $782.00
Liberal: $947.20

The chart also gives suggested amounts for adjusting up or down for additional family members based on age and gender.