There is a certain class of mobile known collectively as 'shopkeepers.'  A
shopkeeper's primary function is to provide objects to players at a price.
These objects include food, clothing, weapons, etc., and the shopkeepers
charge varying amounts of gold for the objects they sell.  When you trade with
a shopkeeper, the number of coins are automatically added to or subtracted
from your purse.  The coins MUST be in your purse, not in other containers.

Shopkeeper commands: Buy, Sell, Value, List

See Also: Bankers, Innkeepers, Mobiles, Purse