Different regions produce different stuff. Some things are more valuable than others. Part twenty-five of my 2021 Worldbuilding Challenge inspired by this reddit post from a person named Faranesque:
School of Commerce, Beginner Lecture, by Professor Nieman Johnson
Everyones country has its own special goods. Every region in that country also has their own wants and needs. No, you can’t just make a living selling potatoes from one village to another. That is not how this works. Almost everyone has potatoes, there is mostly no need for it.
But if you wanted, for example, to sell potatoes to the citizens of Ohm, well, that would actually be a good idea. As they live underwater. And don’t have them already.
You see it’s all about perspective. One thing can be completely useless to one person and the best shit to another. You just have to find what it is they desire. It helps though, if you know what is widely available. So let me give you a short summary of what the different places produce, right.
Old and broken technology and weapons. Mostly weapons. All kind of weapons. Long ones, short ones, some with pointy ends and some with blunt ends. Some are very poisonous and will kill you by just being near you and others will have long lasting effects on your health. Most do both. If you can get your hands on it, try to buy some Acheore. They are really reluctant about exporting this stuff, so you probably have to do some talking to get it.
The Drowned Nation of Ohm
Get some of those deep sea crystals. Those that light up, whenever a living being steps near them. Great for interior design. Also good for detecting otherworldly beings or the dead. Also, if you are really lucky and savy with your sword you can take a god. Not a really powerful one, but one of those godsparks. Just put them in a tightly sealed bottle filled with blessed water. Not sure what you can do with those, but certain individuals really like them.
The Endless Trainworks
One of the more darker craftsmanship is that of emotion-tapping. Willing suspects get their emotions drained in a long and often painful process. Believe me, it is not a nice thing to live trough, but those little shards of iridescent color are worth the pain of others. You can practically sell them in any high-end club to some snob with too much money. Or you can take them yourself. And get addicted. And end up in some gutter, poor and hungry.