The exchange relationships were governed by the barter system. Barter was the foundation of all the commercial activity. This means of exchange has been in existence for thousands of years is Africa.
An example of this barter exchange is after a tribe had reached their destination they would unload their goods in small bunches, give a signal and then retreat. The merchants would come over in front of each bundle and place a quantity of gold dust they judged it to be worth, then withdraw. The former then would come back and impact the amount if they were not satisfied and the cycle was repeated. This was all conducted without direct contact. If they were swindled, they could suspend relations with any given group of traders so identified.
The currency used consisted of salt, cow, or gold in either dust or pieces. Africa was distinguished in the world for its legendary wealth.
The export materials were gold, tin, iron, and precious stones etc. East Africa's primary goods were cola nuts, cereals, and also weaponry: spears, javelins, bows and arrows, also the large production of glass produced in Bennin. Commerce between East Africa and India and China was common under the great Monomtapa monarchy.
In West Africa the products imported were wheat, raisins, figs, sharan, sale, copper, dates, olives, silk, and also tobacco was introduced.
The normal mode of transportation in the interior of Africa was by donkey, ox, and camel or horse. Most of the trading of imports and exports was carried out by the Arabs. Since ancient times the Africans virtually never left their homelands. From an economic viewpoint, the Africans were characterized by abundance. Thus the Africans didn't have a great need to leave their homelands to trade. This was don by the outsiders.