At some point you will want to sell off some items or purchase some new ones. NPCs in Ryzom sell equipment, resources, pets, and even housing. You can usually tell what type of items an NPC will sell by their title. To see what an NPC has for sale and to make a purchase, select the NPC and choose the Trade action - this will usually be the default.

The resulting window will list the items that an NPC has for sale, and their cost, on the right. To view detailed information on any of these items, right-click on them to bring up the status window. On the left, you'll find your own inventory, along with tabs to view other inventories you have access to (such as your mount or packers). At the bottom of the window you'll find your dapper display, which lets you know how much currency you have available.

Next to each item in the listing is the Price. For items in the shop inventory, the price is for each individual item. For items in your own inventory, the price displayed is for the entire stack. To buy or sell any item in the listing, left-click on it once. This will bring up an information window which will allow you to specify the quantity to buy or sell.