At the Kennedy Center for the Performing Arts in Washington, D.C., if you make a $120 donation per year, you are allowed to go to a small room before the concert and drink free coffee and eat free cookies. If you make a donation of $1,200 per year, you are allowed to go to a different small room before the concert and drink the same free coffee and eat the same free cookies. There are always a lot of people in both rooms before the concert: Why doesn’t everybody just pay the $120 instead of the higher price?