WildStar Game Guide:Auctions Analysis
Crafting Aucioner,It is an NPC, of the name of Commodity Broker, who is standing in the Capital City and he lets you buy and sell all of the material that can be used for crafting.
In the window, there are four tabs and the "Buy Now" tab is connected with "Create Sell Order", and "Sell Now" with "Create Buy Order". The reason for that is that, since you can put up an item to sell, at a given price, someone else may want to buy that item, at a lower price. If someone needs quick money, there is an option to access "Sell now" and sell all of the materials to someone who ordered a buy, at their price.
You need to remember, however, that you can neither buy, nor sell too many materials, at a time. The system will then stack up all of the offered goods into one and you then need to buy ten of a kind, because the price for, e.g. the eleventh piece may change.
Aucionner in the Capital City, surrounded by the two other merchants, allows you to buy and sell, on the auction, all of the weapons and the other equipment. There are two tabs here. Buy Items allows you to view the list of goods that the other players wish to sell (unlike in the case of the Crafting Auctions, not stacked anymore), and Sell items allows you to sell them at the auction, along with displaying the other items put up for the auction, so that you can see what the prices on a given item are.