[jfroma]

Say the central bank of XYZ set a fixed rate of 100 $xyz per USD but it becomes illegal to buy USD and no any bank is willing to sell you USD. In a country like the United States you might hedge against inflation by buying some treasuries.. but in other places they just make it illegal to do anything else.

This automatically creates a “black market” of USD where the price is whatever the people are willing to pay, in the end the free market finds its way.

[lottin]

Again, a black market is not a free market. A free market exists within a legal framework in which rules are enforced. In contrast, a black market is a clandestine market, where illegal transactions take place. This means, for example, that participants in the black market don't have legal recourse in the event of fraud.

[jfroma]

“ In economics, a free market is a system in which the prices for goods and services are self-regulated by buyers and sellers negotiating in an open market without market coercions. In a free market, the laws and forces of supply and demand are free from any intervention by a government or other authority other than those interventions which are made to prohibit market coercions.”

https://en.m.wikipedia.org/wiki/Free_market