A common misconception. Marx’s theory of value is specifically regarding generalized commodity production under capitalism. It does not govern every single exchange in a capitalist economy. For example, something that is produced or traded solely for exchange value (like a Trump-shaped crisp) is not a commodity; the theory of value doesn’t apply. The theory of value actually can explain why two basketballs - one signed by LeBron, the other not - can sell for two different prices. The unsigned ball is a commodity, the ‘Bron ball isn’t.
Another common misconception: value =/= price. They're heavily correlated, but not 1 to 1
Read Value, Price, and Profit for a good explanation.
Prices are a reflection of the total labor value contained within a commodity (reified and added, wages and surplus).
And as CleverOleg said, this is essentially a thermodynamic law of commodity production. The value of a unique item is nothing, but some one may be willing to sacrifice their accumulated labor value for it.
This is also why so many capitalists are obsessed with loot boxes, collectibles, etc. now because the price of the commodity can be almost totally unlinked from its value. It's essentially commodified gambling where the actual productive value of the commodities is set by usually a industrial contractor company in China while the prices are set by a finance company in America.
A sports star puts in a lot of good work before becoming famous, though. That is what makes his signature valuable.
Marx failed to consider the image of the Holy Virgin Mary on a piece of toast.
Are there chuds who would buy that? Can art majors pay off their student debt in the funniest and most appropriate way possible?
Bro your sign value? Baudrillard can be incoherent rambling to a degree but his early stuff at least is pretty on point at analyzing some whacky phenomena that arose well after Marx