We've been able to trade games for Team Fortress 2 items since last year. Expanding on that functionality, today Valve has made TF2 items sellable for real moneydollars through the new Steam Community Market public beta—with the caveat, of course, that Steam Wallet bucks can't be extracted from Valve's service.
The Market's few categories remain limited to TF2 gear (paints, keys, and crates) for now, but Valve says they “may expand to include additional items from TF2 as well as items from other games” after beta. Considering TF2's roaring trade economy already allows you to barter unredeemed game gift codes for items, doling out Wallet dough isn't a major difference.
Also notable: Purchasing items carries a 5 percent anti-fraud transaction fee and a 10 percent TF2 fee collected by Steam, with the latter representing “a game-specific fee determined and collected by the publisher.” For the moment, a $200 limit on the maximum price (no minimum price) of individual items stands in effect. Both are open to change, Valve says, but baseline Market policy entails all purchases being final and non-refundable.
Head into the Market to browse a rapidly expanding listing of nearly 45,000 items. I half-expect some sort of hat tax when they inevitably show up on the Market as part of Valve's diabolical plan to leave the video game industry and build a monopolistic headwear empire.