Item Market
The Item Market is the default market place on NoxiousOT. Most players use it to offer their items in exchange for an amount in a certain Currency: usually Coins, Noxious Tokens or Premium Points
On the website
The market is best viewed on the webpage of NoxiousOT, since it gives you a nice visual of the items that are for sale. You can filter on Character Name, Item Name or Attribute. The Market Website can be found here.
In-game
There are several in-game commands to view the information of an item on the market. Mostly, however, the commands are used to put an item up for sale or return it to the original owner. The help page with all the in-game commands is located here.