To sell an item, locate it on the market and select it. There is a button above the other listings, titled "Sell on Market Board." When clicked, a user can choose how many of the item to sell (up to 99 of the item) and how much to sell it for. There is a 5% fee that is taken off of the profit the user makes, this is for Doug to use for his Market.
The price of an item can be changed, or the item can be removed from the Market Board all together, on the "My Sales" tab when the item is selected.
Items can be purchased from other users, each item, if available, has each listing underneath the amount of Credits that the user currently has. Each listing has the price of each of the selected item, the quantity being sold, and how many Credits it will cost it total. Below the purchasable items, a history table with the most recent purchases will be shown with the amount, price, and date sold.
Note: Portions of a listing cannot be purchased separately, what is listed is how much the user will get when they purchase it.