Why don't most tax expenditures help much if your federal tax bill is zero? You don't qualify for tax breaks if your federal tax bill is zero. Taxes are an automatic stabilizer. Most tax expenditures are specifically for high-income people. Most tax breaks reduce taxable income, but reducing taxable income below zero does not reduce the tax bill.

The school cafeteria can make pizza for approximately $0.30 a slice. the cost of kitchen use and cafeteria staff runs about $200 per day. the pizza den nearby will deliver whole pizzas for $9.00 each. the cafeteria staff cuts the pizza into eight slices and serves them in the usual cafeteria line. with no cooking duties, the staff can be reduced by half, for a fixed cost of $75 per day. should the school cafeteria make or buy its pizzas?