Purchasing the brain

A client of a hospital where they made brain transplantations asked about the prices.

The doctor said, "Well, this Ph.D. brain costs $10,000. This brain belonged to a NASA top scientist and costs $15,000. Here we have a policeman's brain as well. It costs $50,000."

The client asked, "What? How's that possible?"

The doctor replied, "You see, it's totally unused."