I sell new and used computers for a living. At an exhibit and sale, I decided to give away an old 13-inch monitor that I had lying around. My neighbor came by and said, "You're giving this away? I'll take it!" Then she noticed a 15-inch monitor at the end of my table. "How much for that one?"

She asked.

I told her it was $75. She looked down at her free monitor, thought for a moment and asked, "Do you take trade-ins?"