Explanation:

"The real price of everything, what every thing really costs to the man who wants to require it, is the toil and trouble of acquiring it. David Ricardo made this statement. David Ricardo (1772–1823) was a classical economist best known for his theory on wages and profit, labor theory of value, theory of comparative advantage, and theory of rents. David Ricardo and several other economists also simultaneously and independently discovered the law of diminishing marginal returns.