For a good to be exchanged between a seller and a buyer, what must be true about their willingness to pay and accept?

For a successful exchange to take place between a buyer and a seller, the buyer's maximum willingness-to-pay needs to be greater than the seller's minimum willingness-to-accept. This creates a scenario where the buyer perceives the good as providing utility or satisfaction that exceeds the cost they must incur to procure it, while the seller values the payment they receive as greater than or equal to the cost or value they ascribe to the good being sold.

When the buyer's maximum willingness-to-pay exceeds the seller's minimum willingness-to-accept, a potential surplus is created, leading to an incentive for both parties to engage in the transaction. This surplus reflects the benefits or gains each party perceives from the exchange. If the willingness-to-pay were less than or equal to the willingness-to-accept, it would result in no transaction occurring, as either the buyer would not find value in the exchange, or the seller would not see benefit in selling the good at that price.

Thus, the dynamic of mutual benefit, where the buyer gains more utility than the currency spent, and the seller receives compensation that they value more than the good they are offering, underpins the necessity for this relationship in successful exchanges.