A Day at the Market in Mesopotamia

Lets say that at the beginning of civilization, you are an artisan, a worker who is specially skilled in crafting items by hand, and you are at the market one day to get the crops and meat that you need. What are the things that you need to have access to them and be able to take them home with you? In Mesopotamia was when trade first started and so during that time many different villages and cities came together to other places to trade their things, so in order to take something you would need to bring something for the switch of items or food. You could bring anything you like, but there is no guarantee that what you want is what the other person needs. At the market you would see new things that your city does not have. That is how ideas and foods spread through cultures, cultural diffusion. Lets Say a village has a surplus of food, that means they can take it to the market and risk giving it away for a smaller value, or raise it higher because they can. It also depends on the village or city that you are taking things from how much or what you would have to give, they will only take what is useful to either them or the village. Obviously there is no complete rule about how the trade worked back then, but there were still laws made by the government and king. So really trade was actually a very universal thing....