The marketplace is the component of each town where travelers can trade for various goods. Every town has 4 merchants, each one only able to sell a specific type of good, but able to purchase anything you wish to sell.
The Weaponsmith is in charge of selling weapons, including melee weapons, ranged weapons, and shields.
The Armorer is the merchant who specializes in armor, covering the head, body, legs, and arms.
The Horse Merchant has a stock of horses of varying quality.
Finally, the (Goods) Merchant sells a range of goods including food, raw materials, and finished products.
The easiest way to access the merchants is to select them via the Marketplace submenu for the town you are currently in. Alternatively, you may walk through the town yourself to look for them. While the Weaponsmith, Armorer, and Horse Merchant can all be found outdoors, the Goods Merchant is located inside of a shop.