The subjective theory contrasts with intrinsic theories of value, such as the labor theory of value which holds that the economic value of a thing is contingent upon how much labor was exerted in producing it. For example David Ricardo said, "The value of a commodity, or the quantity of any other commodity for which it will exchange, depends on the relative quantity of labour which is necessary for its production, and not as the greater or less compensation which is paid for that labour."
In the context of a free market, several major conclusions follow from the theory. The theory contrasts with normative versions of the labor theory of value that say the exchange value of a good should be proportional to how much labor went into producing it. The subjective theory of value is a denial of intrinsic value. It leads to the conclusion that there is no proper price of a good or service other than the rate at which it trades in a free market. Whereas the labor theory of value has been used to condemn profit as exploitation, the subjective theory of value rebuts that condemnation: a buyer in a free market who offers to pay a price lower than that which is commensurate with the amount of labor used to produce the good merely communicates information to the seller about the value the good might create for the buyer. (The price offered is not a measure of subjective value; it is just a means of communication between the buyer and the seller.) The offer is in one sense an expression of the buyer's opinion, which the seller is free to reject.
Indeed, the subjective theory of value supports the inference that all voluntary trade is mutually beneficial. An individual purchases a thing because he values it more than he values what he offers in trade; otherwise he wouldn't make the trade, but would keep the thing he values more highly. Likewise, the seller agrees to trade only if he values the good less than the price he receives. In a free market, both parties therefore enter the exchange in the belief that they will receive more value than they transfer to the other party.
In turn, this leads to a third important conclusion: the mere act of voluntary trade increases total wealth in society, where wealth is understood to refer to an individual's subjective valuation of all of his possessions. In contrast to intrinsic-value theories, which tend to support the conclusion either that wealth creation is impossible (zero-sum), or that wealth creation is possible only by the application of labor, the subjective-value theory holds that one can create value simply by transferring ownership of a thing to someone who values it more highly, without necessarily modifying that thing.
While earlier economic schools such as medieval Scholastics and French Economists of the 18th and 19th century implicitly used the STV, it was formalized by the Austrian School with the notion of marginal utility by Carl Menger, who said: "The measure of value is entirely subjective in nature, and for this reason a good can have great value to one economizing individual, little value to another, and no value at all to a third, depending upon the differences in their requirements and available amounts...Hence not only the nature but also the measure of value is subjective. Goods always have value to certain economizing individuals and this value is also determined only by these individuals." (Principles of Economics)