Suppose Jill Johnson operates her pizza restaurant in a building she owns in the center of the city. Similar buildings in the neighborhood rent for $4,000 per month. Jill is considering selling her building and renting space in the suburbs for $3,000 per month. Jill decides not to make the move. She reasons, "I would like to have a restaurant in the suburbs, but I pay no rent for my restaurant now, and I don't want to see my costs rise by $3,000 per month."