Opportunity cost is one of the most important concepts in economics. Economists will tell you it is the correct/true way to conceive of costs. In a nutshell, it is everything foregone. To make sure you correctly capture the opportunity cost of a decision, take time to assess the explicit and implicit cost.
Finally, why is there no such thing as a free lunch, because every decision has implicit costs. True, not every decision has explicit costs, but every decision results in something foregone (in fact, that's what makes a decision a decision). Therefore, it is true, there is no such thing as a free lunch.
This video is made for 1st year college students or AP/IB Economics students. It focuses on foundational economic concepts.
