The brand new Steam Community Market is now live and available for the Team Fortress 2 community in beta mode.
The Community Market is an addition to the Steam Trading system where users will be able to sell their items for Steam Wallet money which they then can use to purchase other content available on Steam.
The market will allow users to easily search items that are up for sale and aid sellers in delivering their products much better. With this initial launch of the system, the market is limited to one-time consumable items until the process is refined further. All activity on the market will be subjected to transaction fees. You can read all about it here and more on the related FAQ here.
You can also give feedback about the system via the official group on Steam.