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.