An evening spent at work cannot also be spent studying: choosing one uses time that could serve the other.
01
Go deeper
The cost can involve time, enjoyment or money. It is the next-best forgone option, not the sum of every possible alternative. The same logic applies to government and business budgets.
02
Make it concrete
Hypothetical illustration. Hypothetically, the best alternative to a free evening event is a $40 shift. The forgone earnings are part of its opportunity cost.
03
When you read a headline
A zero ticket price does not mean a choice uses no scarce resources.