Merchants sell basic supplies

Merchants sell basic supplies, such as Identification Kits that tell you exactly what a magical item in your inventory does, or Salvage Kits that allow you to recover crafting materials from otherwise useless loot. Merchants, like other vendors, will buy all manner of items from you—weapons and armor, found items, dye, and crafting materials. Look for [Merchant] after the NPCs name when you're looking to trade. If your alliance controls a town, the Merchant in that town will give you a discount when you purchase items. http://www.guildwars.com/gameplay/exploring/townlandscape/