ELI5: Explain Like I'm 5

Opportunity cost

Opportunity cost is something that happens when you choose one thing over another. It means that by choosing one thing, you are missing out on something else. For example, if you have $10 in your pocket and you spend it on an ice cream cone, then you cannot spend it on something else, like a toy. So, the opportunity cost of buying the ice cream cone is that you lost out on the toy.