In my country there is a huge economy deflation.
Like 1 year ago 1USD used to be 1500 pounds.
Nowadays 1USD is more like 7800 pounds.

Wait a second let me explain more into details the whole flow.

There are 3 to 4 prices we are being dealing with:
* Official Bank price that refuse to change the base price: 1500 pounds
* Bank ATM machines that exchange your dollars on a 3900 pounds per usd
* Black market: 7800 pounds managed by random mobile apps that spread rumors
* Foreigners currency: the only way to grab your reach dollars.

Long story short:
Whenever you want to win extra cash, you ask any of your relatives to lend you money from any bank in the world ( foreigners currency), try to ask in black market who is willing to exchange, you meet, you check on any mobile app what's the current price and you do the exchange.

So in order buy USD dollars on a low price, devs build 2 mobile apps one that send a POST request to change the amount in DB and a second one fo retrieve this value.
So whenever he want to buy dollars he change the value to the lowest. And whenever you want to sell the dev raise the amount slowly. So far the government has no regulations over developers why? Because the one behind the forensic are at least 60 to 70 years old more like their informations are dead.

So we struggle.