What kingdom was built off of gold and salt collected as tolls?

The kingdom built off of gold and salt collected as tolls is the Ghana Empire, which thrived in West Africa from around the 6th to 13th centuries. It became prosperous due to its strategic location along trade routes, facilitating the exchange of gold, salt, and other goods. The wealth generated from these resources allowed the empire to flourish, leading to significant cultural and economic development in the region.