Stoller [saying nothing that hasn't been said before]:
All commodities (averaging out socially necessary labor-time) are exchanged (sold) for their TRUE value.
: Ok, when one accepts the concepts of surplus-value and socially necessary labor-time as true, then one would be able to logically say that a man who has hired a worker and does not pay them what their product is worth (thus making profit) is essentially stealing from the worker.
That's the conclusion drawn by Marx, yes.
: My question is how this works in relation to consumers. If a self-employed worker makes shoes, after calculating the socially necessary labor time and the standard value of the shoes (taking into account quality and cost of materials) and he determines that one pair of shoes is worth $20. Would he be bamboozling the consumer if he charged $30? $50? $100?
You answer that (imagining yourself as a consumer).
: Now, assume that this worker has a monopoly on selling shoes, that is, he is the only shoe manufacturer in his town. Would it be alright for him to charge enough so that he could break even and still earn a decent living? What if he charged ludicrous amounts and lived a luxurious life-style? (Keep in mind that I am assuming that no other competition will move in to put him out of business.)
Your 'ethical' question is besides the (Marxist) point.
Engels: 'The price of a commodity is on the average always equal to its costs of production' (Principles of Communism, Monthly Review Press 1952, p. 7).
Capital is characterized largely by competition---the never ending pursuit of cheaper methods in which to produce commodities (in order to undersell competitors). Since the industrial revolution, one very significant method of producing cheaper is to produce MORE (while paying labor the same as before per aliquot commodity). The 'local' shoe maker will eventually meet his maker---in the form of Sam Walton.
That's capitalism. One capitalist kills many.
Competition, therefore,---in the form of cartels and mergers---does has a natural dialectic leading to monopoly. This is because centralization itself can produce so much more an for less than small producers can produce. However: This is not to say that any monopoly is ever absolute; national monopolies inevitably confront OTHER national monopolies (and trade wars evolve into world wars).
The process of capital---even at its most monopolistic---is a (incredibly dynamic) process of finding new technologies in which to constantly UNDERSELL capitalist competitors. This, in many ways, is the progressive trait of capital (but I'd give more credit to the technology---i.e. the mode of production---than to those who use and often abuse it---i.e. the social relations that attend the mode of production).
In my opinion, the lesson to be learned by capital's internal logic of development is that centralization (and with it automation, rationalization, etc.) itself is the most valuable quality that capital offers FOR the socialist future.
Of course, if your living comes from petty proprietorship, then capital's inexorable drive toward centralization (one capitalist kills many) will seem like a very destructive force, not a progressive one at all...