Opportunity cost
You have $50. You can either buy a new book for $50 or go to the movies with friends. What is the opportunity cost of buying the book?
The fun experience you would have had at the movies
You have one free hour. You can either study for an upcoming test or go out to play basketball. What is the opportunity cost of studying for the test?
The time spent playing basketball
You are given $100. You can either buy a pair of shoes for $100 or save the money for a future trip. What is the opportunity cost of buying the shoes?
The future trip you would have been able to take