Answer:
True
Step-by-step explanation:
Every resource is scarce, starting with time. When you decide to study for a test or just to know more about some specific topic, you are incurring in opportunity costs. You could be watching TV, playing PC games or PS4, sleeping, going to the gym, etc., instead of studying, but you value the knowledge more than those other options.
The same happens to money and all the other resources, you decide to use them (spend them) or keep them for a later use that provides larger benefits. But you must always trade one thing for something else, e.g. buy now and enjoy, or but later and enjoy more.