If I'm doing well and flush with cash, and I would like to buy a nice guitar, and have the time and the knowledge to pursue the classified ads in search for one so as to avoid paying the full sticker price, I might be able to locate someone selling the nice guitar I want for a fraction of the original price.
This person might be desperate for some cash, or be in a hurry and selling surplus items to move, or the person might be moving away from a brief flirtation with musical interest, or it could be someone who came into possession of the original owner's instrument, and therefore, much more willing to part consensually from such an object in exchange for less than it is worth.
I myself was in this position almost a decade ago: I needed to scrape together some money for a new car/mobile apartment I really needed, and the best possible objects of sacrifice were a beautiful Warwick bass and a Gibson SG guitar, which through their superfluity and concentrated value, yielded quick enough and concentrated enough cash infusions to serve my purposes. And I still think of them and miss them. But then with their help I was able to get the cash together I needed for the car, and to this day this Honda Element is an indispensable possession, given the structure of our society.
There are a lot of ways in which this can happen, but the end result is that someone in ideal conditions - plenty of money, time and energy to burn, stable living conditions, etc. - is able to acquire a desired object from someone in less than ideal conditions - a shortage of time and energy, pressing needs, an absence of knowledge, etc. - with an unequal transfer of resources. That is, a product of universally commensurable human labor - represented by money - is acquired by someone for a relative fraction of the resources that went into producing and maintaining that product.
In daily life, theoretically a lot of this should be relatively benign. People want different things at different times in different circumstances, and sometimes someone is getting a better deal than the other party, but both parties get to walk away with what they want or need at the time, and ideally the various incommensurable resources - all requiring differing hours of labor time and differing amounts and sourcing of resources - circulate and eventually seek out the places where they are needed. My own situation was closer to tolerable than not: however unfortunate my shortage of cash was, I had the means to give up relatively superfluous articles of property to acquire a resource I did need. But plenty of sellers aren't so lucky.
And we're not talking theory or ideal here. Because of course, concentrated power has discovered the advantages of these various forms of arbitrage and systematized and instrumentalized them as tools to further its own preservation and augmentation, and today this is basically refined to an art and science.
Which has been going on for a very long time, at least all of the way back to ancient forms of trade arbitrage and the emergence of early merchant capital: buying low in once place of advantage and selling dear in another. And we've had a lot of time to deepen and perfect these various games.
But today, one thing that unequal exchange does, is that it better distributes the negative effects of applying force, which in effect extends the benefits to power through time after applying that original force. How this is accomplished can be illustrated in a classic example: the exchange of labor power for money. On paper this exchange looks fine enough: I put in the requested work for some agreed-upon amount of money(another can of worms) which I then receive to buy food, clothing, housing, etc. Gee, thanks boss!
But the very fact of my needing money for food, clothing, and housing, and the requirement that I alienate my labor for that money, and the fact that there are classes out there that possess the stores of money above and beyond the replacement of their own necessities, so that they can offer that money to purchase the alienated labor of others, can all be traced way back to the breakdown of the feudal system, the enclosure movements, and the expropriation of the land originally worked by the peasants, leading to an increasingly generalized creation of a landless proletariat who had to work not to directly sustain their households, but to earn the money to buy their necessities and pay rent to landowners who were consolidating newly enclosed land resources.
And of course, this original process required an enormous amount of force and violence to remove people from their lands and force them into factories and piecemeal agriculture work raising monocrops, and resisting holdouts were harshly punished with early vagrancy laws. Needless to say, this was a complex process that went on for centuries, which we'll have to gloss over for now. As always here I'll repeat that it is much more complicated.
What matters though is that the original injustice was never reversed, but increasingly padded over with the passage of time and insulating layers of abstracting mediation in the form of various types of capital and their supporting propaganda. The heavy lifting of removing vast swathes of population from the land was done, and that basic structural injustice has been left in place up into today, which structures the basic way in which the class game can be continuously played, the original act of exploitation repeated again and again, day by day.
And this state of affairs is itself treated as a resource to be maintained. Indeed, it could be considered a form of wealth in itself. Much like the fossilized and compressed plant matter that can be sucked out of the ground as oil, a given stage of human development produces value of a certain quality which can be harvested, and the various gradations of the value chain can be cordoned off geographically and manipulated to yield the quality of product desired, so long as the great powers possess the means and ability to do so.
These human developments can take a very long time, though we've seen historical periods of rapid industrialization happen in leaps and bounds, though the conditions for that can be quite complex and contingent as well. Because of these long time frames, and complex historical contingents, a lot of energy and effort is put into maintaining a given level of development for arbitrage and harvest, for example in the relationship between the imperial core and peripheral colonial or post-colonial possessions, which is part of why you see terrible deeds committed in meddling, coups, propping up of dictators, brushfire wars and operations, and etc.
Much more could be said in a more skilled fashion, but for now I'll leave this general picture, and elaborate further in various ways in time.
