Given shortage, firms can choose how they will discriminate. Regular customers often benefit. Price floors are legislatively imposed minimum prices. Set above equilibrium price to be effective. Artificially high price leads to a persistent surplus.
High price decreases quantity demanded.
High price increases quantity supplied. Persistent surplus requires some mechanism to remove the excess supplies from the market. Government purchases surpluses create by farm price supports. Impact on taxpayers government expenditures on surplus price floor times surplus government expenditures on storing the surplus. Demand shifts to the right.