So I think I know what I want to do with my Cargo mechanic, and it looks almost identical to the original cards I had when I started this project.
Take a look:
Here we have the original City Production Card I was using at the beginning of the month. Each city will randomly receive one of these cards to shake up the predictability of the best trade routes. This card shows each type of merchandise with a number value. The Number Value is the amount of production the city creates of each type of merchandise. Each turn you would place that many Colored Cubes for each type of Cargo. Once the Cargo exceeded a certain amount the cargo would automatically be moved to adjacent cities. This is intended to simulate supply, demand, and other traders competing in the same market.
Now here is the new idea for the City Cards....can you tell the difference. I am not talking about the obvious changes like the arrows or the red colored text.
It's the meaning behind the numbers. On this Card the numbers show the cost of each good in this city instead of the production number. Huge difference! The arrows indicate the merchandise that the city produces and the red numbers indicate high costs of products that are in demand. I don't bother with how much cargo is produced, players can buy as much as they want (assuming they have the Cargo Space on their ship).
Simplifying these cards to just show cost and eliminating the Cargo Production will loose the more realistic economy I was building. The upside is that this will make the game flow much nicer and will be much better for the game in the long run. People can enjoy your game if they are mired in tedious management and bureaucracy tasks.