There is no money that goes anywhere.

Imagine you have a rare comic book and I tell you I’d pay you $100 for it, you turn me down. A week later, you need money to buy your mom a birthday present and ask if I want to buy it. But now, I only offer you $80 and you begrudgingly take it. There is no $20 of yours that went anywhere — I was only willing to pay less for something you have.