What were items that Ghana, Mali, and Songhai used to trade

it was a great cosmopolitan market place where kola nuts, gold, ivory, slaves, spices, palm oil and precious woods were traded in exchange for salt, cloth, arms, horses and copper. Islam had been introduced to the royal court of Songhai in 1019, but most people remained faithful to their traditional religion.

Explanation:

An example is gold and salt. Other ones that were traded commonly were:

ivory, kola nuts, cloth, slaves, metal goods, and beads.