The two most popular in-demand items for trade were gold and salt. People from North Africa wanted gold while the people who lived in the southern forests wanted salt.
Only the local Wangarans knew the location of the gold mines. Even when captured, the Wangarans still kept the locations a secret to prevent outsiders from finding them.
The city that had a salt source below it was the city of Taghaza. Salt was so important to the point that Taghaza would have never existed if the salt was not there.
Ghana charged ⅙ of an ounce of gold for each load of salt that came into their kingdom from the north. But for traders who came in from the south, they charged ⅓ of an ounce of gold for each load the traders took out of the kingdom.
Ghana used their tax money to pay armies to help protect their country, to conquer other places, and to protect trade routes.
The largest market in West Africa at the time was located in the city of Kumbi. There were many things people could buy such as food, cattle, water, slaves, and many more other things