How did the trans-saharan trade lead to west african wealth and success?

North African traders brought goods through Ghana and were taxed coming in and out depending on how many things they had. This was a huge source of income for Ghana.

western africa benefitted from the Trans - Saharan trade because each time trades came in they were taxed and  western africa became very wealthy because of this.  Walking across the Sahara was so hard because caravans sometimes lost their way, and some traders died in the desert.

i believe it was spain