I Want to Know About Eorzean Economics

[Jpec07]

In what is quite possibly the most riveting discussion topic I could have ever conceived, I am taking to the forums to ask about Eorzean economics.

I'm trying to come up with a character for roleplay purposes who is a bit of a tycoon - a merchant of sorts who is very keen on investments, and who knows how to turn stock into profit (taking a page from Kraft Lawrence of Spice & Wolf). But in doing so, I realized that I know almost nothing about economics in Eorzea, which puts a big hole in my ability to play this character.

So, Lore Hounds, what do we know? How do the city states' economies function and grow? Do any of them have any policies in place for specific commodities that we know of? What are their chief exports and imports, and do we have any info on GDP? How do these organizations make the money they need to support their operations?