The natural price, therefore, is, as it were, the central price, to which the prices of all commodities are continually gravitating.
Adam SmithIt appears, accordingly, from the experience of all ages and nations, I believe, that the work done by freemen comes cheaper in the end than that performed by slaves.
Adam SmithThe real price of everything, what everything really costs to the man who wants to acquire it, is the toil and trouble of acquiring it.
Adam Smith