Answer: The real cost of something is what you must give up to get it
Step-by-step explanation:
Based on the information given, the economic principle that's illustrated in the question is "The real cost of something is what you must give up to get it".
It should be noted that the concept of opportunity cost is illustrated. In this concept, for an economic agent to do a particular thing, something else must be forgone. In this case, it is the real cost if what we forgo. For this to happen, a trade off has to occur.