This is just a little game while I work on Bezzquest. I removed the ability to buy/sell slaves since ST wouldn't like that. The pile of coins represents your Shekels (the currency of many ancient countries, including Carthage). The wheat represents Food, the cloth is Textile and the ingot is Metal. Note you can get 99 MAX of each merchandise type at a time. If touching a city (the red rectangle) press space to trade. You can only sell stuff if it is the stuff a city demands. However, you cannot buy that type of merchandise while that city wants said merchandise. The rest is pretty intuitive. I may add pirates.
All made by me. The map took a while.