I traded the Vintage Timebreaker mace from Dota 2 last night for Fable 3 and Civ 5: Game of the year. Most people believe the mace is worth around $10-$13. Not bad for receiving 2 games that both retail for $49.99 and go on sale for $12.49 each.
Anyone else use Steam trading often? I have a few more rare items that people were asking for, so I might trade those away as well. After my trade, a friend of mine traded his for two copies of Chivalry.