Charlie used his $500 as a medium of exchange.
In this context, the $500 serves as a means to facilitate the transaction of purchasing the truck, allowing Charlie to exchange it for the vehicle.
- A store of value refers to an asset that can maintain its value over time (like savings or investments).
- A unit of account is a standard numerical unit of measurement that provides a consistent measure of value (like how prices are listed).
In this case, since he is using the money to complete a transaction, it is primarily functioning as a medium of exchange.