What is the listing system?
The listing system is an in-game framework centered around banker NPCs that is supposed to make trading and finding items to buy easier, no matter where in the world you are. It incorporates free listing of items you are selling, tools to browse the sold items of other players, and a mail system to send and sell your goods.
Related commands: /cm listprice, /cm listadd
Let's say you have a leather tunic that you want to sell. You think that five platinum is a fair price for it. You have a few options, such as using the /auc channels or talking to people directly, but by far the simplest way is to use the listing system. First find a banker and open up your bank. In your bank is the "Listing Vault" section, which encompasses two slots - you can extent it to up to twenty slots by placing bags there. Type /cm listprice 5 in order to set the price of the next item you're going to place in the vault to 5 platinum, and then place your leather tunic there. The leather tunic is now listed as being sold for 5 platinum coins.
For someone to see that you are selling it, they need to use /cm listsold on you (see Browsing below). Of course, in order to do so they must know that you exist and are selling things. The simplest way to make sure they can find you is to target a banker and type /cm listadd. This adds you to the active sellers list for a period of 48 (real) hours (during this period you can use /cm listadd again to reset the timer, and keep doing so if you don't want to drop off the list).
Related commands: /cm listsold, /cm listview
Browsing what another player is selling is as simple as typing /cm listsold with them targeted, or by targeting a banker and then putting in a name (like /cm listsold Wiz). This will show you all the items in the player's listing vault, complete with requested prices.
You can get a list of active sellers by using /cm listview <amount> where amount is the number of entries you want shown at once (up to 20). Use this command to see the names of the active sellers along with the comment or two on their wares. When you use the command again, the browsing will continue where the last browse left off, so all you need to do to go through the entire list of active sellers is to keep using the command.
For an online listview: Old version / Updated version
Related commands: /cm listbuy
When viewing a player's selling list, you will see a number next to each item, for example #1. In order to automatically buy that item, simply type /cm listbuy [name of player] 1 while you have a banker targeted and the item will be automatically sent to you for the listed cost. You can not buy items without a listed cost this way.
Related commands: /cm listsend, /cm listget, /cm listaccept, /cm listreject
Sending allows you to send items to other players through the banks, either to sell or simply to give something away. In order to send, you will need to have a banker targeted and the item you want to send on your cursor. Type /cm listsend <name of recipent> <requested price in platinum> and the item will disappear from you and go into the mail system. The receiving player gets a notice that they have mail.
The receiving player now needs to target a banker and use /cm listget. This will show the first mail in their queue, along with the item in it and the attached price request, if any. The recipent can now use /cm listaccept to receive the item into their inventory and pay the requested fee to the bank. The fee, minus a small percentage that the bank takes, is sent back to the sender. The recipent can also use /cm listreject to bounce the item back to the sender, for example if they're not willing to pay the requested amount of money. Any mail which has not either been accepted or rejected for 48 (real) hours is automatically returned to the sender.
The bank takes 2% of all transactions.