I don't believe UrW simulates any exchange of goods between villages and merchants except in very abstract terms: their goods change with the season for farm goods, and other stock is slowly turned over over time.
Merchants are said to be foreign traders from the west, even though their names suggest they're from the southwest. Because of that, their stock doesn't change depending on which customers they visit.
It seems merchants only carry "weapons" and armor, but not "tools" (I'd consider a woodsman's axe to be a tool primarily, but whatever). Since the traders are foreigners selling goods from their home, they won't carry local merchandise.