The law of supply and demand explains how changes in a product's market price relate to its supply and demand. Usually supply and demand keeps the price of homes reasonable.What is price gouging? Price Verification Division. Los Angeles County is strongly committed to price accuracy, and the fair and lawful treatment of consumers. There is an inverse relationship between the supply and prices of goods and services when demand is unchanged. If demand exceeds supply, prices will rise. In a free market, the equilibrium price is the price at which the supply exactly matches the demand.