I'm having a hard time envisioning what trade and commerce looked like in the Bronze Age before the invention of money. I'm particularly interested in ancient Egypt and Mesopotamia but also the cultures of Central and South America (I understand those were from a completely different time period).

I keep reading about how Bronze Age civilisations traded far and wide from Cornwall to the Indus Valley before the invention of money. But it's often mentioned that there was no such thing as a barter economy before the invention of money.

What facilitated commerce and trade? Why would people in Cornwall dig up tin and give it to traders unless they received something in exchange? Does that not involve bartering?

How did the economy in a Sumerian or Minoan city function? Were artisans and scribes paid? Or was everything a planned economy centralised through the aristocracy? (The so called palace economies) Were people in cities able to pay for things or trade for things? Or were they just provided for because they had a particular job or status?

I guess for me there's a blank space in my understanding. I read about trade routes and Sumerian accountants and taxes and levies, markets and trading ports but all of this happened without money or bartering for goods.

Hope someone can shed light on this topic.