Commerce

Import/Export

They make the best silk and musical instruments. Their primary import is wood. While they're surrounded by the Draewood, it is taboo to cut down any of its trees. They export cut and polished gems, fine jewelry, musical instruments, clothing, and high quality cloth.
The siathi settled there for its abundance of mineral resources. Most of these resources were depleted by raising the Towers, but there’s still a decent amount left to be found.

Guilds

Guilds exist to maintain standards, ensure that prices remain fair, and that the education given to students with the aptitude for that vocation is up to the current standards. They also have a faction inside each guild that always looks for ways to improve methods, sometimes sending members to visit sibling guilds in the Provinces to learn their methods.
Cross crafting largely depends on an individual's aptitude, training, and opportunity. Silk weavers will sometimes craft lace as well, for example. Farmers can also be tailors. Soldiers almost always have a secondary occupation as there’s rarely any call for the military.
Trades are largely dependent on geography. The northern and western parts of the Valley are better suited to metal work as trade with the outside is easier there. The north still has a decent supply of mineral deposits so the majority of the jewelers are located there. Most of the animal husbandry is in the south where the grazing is the best for sheep and goats. Chickens are more common in the east as are weavers as the silkworms seem to find the humidity.
The siathi are largely insular and didn't really trade much outside of Salcreria until the year 97.

Currency

Salcreria uses the standard currency that comes out of Arrack-Ley.