It's somewhat dynamic, but there are actually some places that get more of certain things, like the Vaegir lands usually have pretty good prices for furs meat and wool, the coastal areas usually offer fish pretty cheap. Salt is cheap in the Khergit areas, as is spice. I've seen Oil cheap in parts of Swadia and Rhodok. I haven't done any extensive testing, just my observations from sparse trading here and there. Usually anything that you can get cheap in one part of the map is expensive on the opposite end of the map, but sometimes a closer city will have an even higher price - so checking prices never hurts.
The best bet to get a profit is to check all the little villages and glance through all their goods for something cheap - get familiar with approximately what you can get for goods and look for something cheap. Many villages have very cheap goods, like 10 denar fish, 11 denar meat, 50 denar oil, etc. I haven't taken the time to do any real testing, but I remember buying cheap oil from the same village near Suno several times, so if you find a deal you might write it down and check back there later for the same. Some villages might be predisposed to cheap prices on certain commodities, I'm not sure.
It's actually kind of messed up right now, as I've seen times where I could buy oil for 50 at a village and sell it for 300 a few steps away at the city. You can really make a bundle on cattle and beef, sometimes you can buy 5 cattle for 10 denars each and sell the 10 meat from them at the nearby city for at least 50-60 denars each, sometimes 80-100. Buying more cattle than the 5 will have the price going up each time, but you can usually buy a few batches before it becomes unprofitable - plenty enough to fill your inventory. I always just slaughter them on the spot because I don't like driving them.
