Steam has trading in beta testing. Everyone can participate.
- GTA: 4
- Half-life 2: Deathmach
- King’s Bounty Armored Princess
- Left 4 Dead
- Max Payne
- Max Payne 2
- Portal 2
- Stargate Resistance
* There are no geo-restrictions.
* No, you cannot trade your own bought games, only received gifts.
* You can drag items to chat window to start trading
* Your trading inventory is under COMMUNITY > Actions > View Inventory
* Currently on sale:
- Team Fortress 2 items
What items can be traded?
Team Fortress 2 items and Steam Gifts can currently be traded in the Steam Trading Beta.
Will there be other games that support trading?
We’re working now with other game developers to incorporate both Trading and Inventories. Portal 2 should be reasonably soon and we hope to have several third-party games in the next few months.
What do you mean by trading Steam Gifts?
Any game you’ve purchased from the store as a gift, or received as an Extra Copy, can be traded to other users. They can be used to trade for other Gifts, or for items in Team Fortress 2. We’ve added a new checkout option to the Store when purchasing a gift so you can save it for trading or sending later, to support users who want to save games for trade fodder.
What restrictions are there on trading Steam Gifts?
Trading a Steam Gift is very similar to sending a gift to someone; just that once it is traded that user can then either trade it again, or open it for themselves. There are no restrictions on territory.
Does Steam Trading mean I can sell my used games?
No, only games that have been bought as a gift, and thus have never been played, can be traded. Once the Steam Gift is opened and added to your game library, you won’t be able to trade it again.
How do I see my Inventory on the Steam Community?
Once you have opted in to the Steam Trading Beta, you can select Community in the Steam client, then on the right is a link to View Inventory.
Who can see my items?
Your inventory obeys your existing regular privacy settings – public, friends only, friends of friends, or private.
More info here