Price determination in Marx

Marx does not think that commodities actual sell at their value in an advanced capitalist economy, but what is his theory of price determination? Here is my effort to explain it according to my understanding.

00:00 Introduction
02:18 The three kinds of price
02:36 Market price
04:24 Price of production
06:47 Constant capital resolves into wages and profit
10:00 Prices of production (summing up)
12:10 Labor value
14:33 Calculating total annual value
15:19 Monetary expression of labor time
16:36 Calculating total surplus value
18:25 Profit rate
20:33 Price determination in Marx

[KamKamKamKam]

I would say there is another (somewhat under explained by Marx and under studied by his readers) concept that comes into play: that of "market value".
Market value is the term Marx actually ends up using (in vol 3 only it seems) when referring to the "center of gravity of market prices".
I'm not exactly sure why he doesn't introduce the term earlier, but once he starts using it he doesn't stop.
If we retroactively apply his terminology, we find that market value (ratio of exchange at the center of gravity of market prices) is first considered to be determined by "value" (SNLT) in volume 1, then once the additional determinant of the "equalizing profit rates" is added, the market value shifts from the "value" towards the "price of production". And then finally, once he adds the concept of rent, we have to take those variables into account as well (differential productivity and so on) when discussing the market value.
I would guess that in an even more fully-fledged version, the talk of market value should also have included the role of the state (taxation and well as subsidies), and the concept of "international market value" when discussing international trade the the effects different currency exchange rate have on the whole thing.

[rainerlippert]

▪ At market price
Statement: The market price is determined by supply and demand.

My view on the market price:
On average, for work products it must include expenses if production is to be continued, improved and, if possible, expanded.

The market price reflects the real value. The value is created when the buyer and seller exchange, among other things, a work product for a value equivalent.
Before the exchange, i.e. the purchase or sale of a product on the market, there is only one expected value for this product.
When it is sold, the product of labor becomes a commodity (according to Marx: Only when a product of work becomes a use value for others through exchange does it become a commodity (and the work can be qualified then as labor).

▪ At the production price
The production price cannot be composed of the costs of producing (and providing) a product and the average profit. The profit is not a cost share but is paid by the buyer on the market.
If a buyer on the market completely replaces the costs of a product (c + v) and also pays more, then the entrepreneur receives surplus value. However, the entrepreneur still has to pay taxes on this, perhaps more. If these additional expenses are deducted proportionately from the surplus value, then the profit remains. But even so, profit is not a cost share of the product.

▪ On socially necessary labor hours
The socially necessary labor time is not the working time that is needed to produce the individual parts of a product and bring them together. This is also not the case if you use the most productive technology for producing this product as the basis for calculation.
On the production side of the commodity society there is only private work in the private sector of the entrepreneur. The production results are also not yet socially useful at this point. As a result, according to Marx, the work done for this was not yet value-creating.

Only when a buyer exchanges the product on the market does he, through the exchange, recognize the usefulness of this product for society. Then, retrospectively, the social working time required for the product can be determined. This is exactly the part of the working time that is paid for by the buyer and is therefore recognized as socially useful. Only this part of working time can be qualified as abstract and therefore value-forming.

If the buyer not only replaces the costs of producing and providing the product, but also pays more, then the entrepreneur receives surplus value. Only then can the shares of the abstract, i.e. socially necessary, working time, i.e. the part that the buyer replaces and the part that the buyer pays but which exceeds the costs of production and provision (surplus value), be determined. This means that only after the product has been sold on the market is it clear what proportion of working time is socially useful and necessary and what proportion is surplus work that creates surplus value (the so-called “unpaid working time”).

Since surplus value is part of value, value cannot exist before the product is sold.
Marx is clearly wrong when he says that surplus value is produced. On the one hand, there is still no surplus value on the production side of the commodity society and, on the other hand, the surplus value is paid to replace the costs and not to the costs, as Marx describes it.

Conclusion
The value is formed in the market.
You can only produce the prerequisites for value creation and surplus values, but neither the values nor the surplus values directly.

[KamKamKamKam]

Great video overall.
One small (but substantial) detail I would be picky on:
Regarding the share of the value (or price of production) added by the means of production. You claim both that the value transmitted by the MoP corresponds to the SNLT of those MoP AND ALSO that it instead corresponds to the amount of capital laid out in the purchase of the MoP (constant capital).
Those are two different quantities in any situation in which the value of the MoP and their market price differ.

If you believe it is the SNLT of production of the MoP that goes into the value of commodity, you are on the side of Ricardo and Shaikh in this debate.
If you instead believe it is the amount of dead labor laid out as constant capital for the purchase of the MoP (at their market price, necessarily) that goes into it, you are on the side of Marx I believe.

Note: The first interpretation (value = direct living labor + indirect living labor) leads to the infamous "transformation problem", while the second (value = direct living labor + dead labor advanced as constant capital) doesn't.