Lots of illegal activities take place in a darknet market or cryptomarket, such as buying and selling drugs, weapons, stolen credit card numbers, and steroids. Others use it simply because they don’t want any government entity watching their internet purchasing activity.
To access a darknet market, you would have to use the same encryption tool as the website, such as “Tor” or “I2P,” and your identity will be hidden as well. The method of payment is usually cryptocurrency so that buyers can’t use those stolen credit card numbers.