In this article, the author Daniel F. Stone found informative debates between Ferraro and Taylor (2005) and Potter and Sanders (2012) about the actual definition of opportunity cost (OC) as it is unclear and controversial. Ferraro and Taylor claimed that most economists do not know its correct definition, and Potter and Sanders argued that this could be clarified by the fact that there is no standard definition. Stone contributes to this debate stating that there are two specifications to the term opportunity cost: an implicit cost and a total economic cost. Stone suggested using the terms implicit and explicit cost to make the logical analysis clearer and an accurate definition of economic cost unquestionable. In Stone’s article, he showed debates on two specifications of units: regarding the value and regarding “physical quantity.” Stone distinguishes the crucial differences between a value and a quantitative specification of opportunity cost. Although, both values and quantities have their place in opportunity cost one ought to know that there are hidden costs. After opportunity cost is comprehended this way, the concept of opportunity cost becomes more knowledgeable about units and the difference between discrete and constant factors.I found that in this article Stone presented many economists that could not define the concept of opportunity cost the same. I understand how these economists could have had different answers to the definition for at first; it was all a little exhausting trying to grasp the understanding of when to use the opportunity cost concept. Stone’s primary goal was to build knowledge and a better understanding on opportunity cost, and in his article, he constructed new knowledge and explained how opportunity cost should include both explicit costs, requires money payment, and implicit costs, does not require money payment. He feels that every choice people make has opportunity costs. Stone addresses the purpose of opportunity cost and gave good examples of how people’s values differ and how opportunity cost can be measured, or the cost can be difficult to quantify by making one choice rather than another. Now I have a better understanding of why the article was titled, “A case in point of no free lunch,” because things that appear free always have hidden costs and as well as hidden benefits.