This lesson explains how to calculate the effects of a per unit subsidy in a commodity market (in this case corn) using linear demand and supply equations. By employing demand and supply equations, we can determine how a per unit subsidy will effect supply, and then we can calculate the new equilibrium price and quantity. To extend our analysis, we can calculate the increase in consumer and producer surplus, the total cost to taxpayers of the subsidy, and thereby the net cost of the subsidy to society as a whole.