Steam Wallet, Steam's new in-game currency solution, is now live and the first game to support it is Team Fortress 2. Team Fortress 2 players can jump into the Team Fortress 2 Mann Co. Store within the game and make purchases. Steam Wallet users can add money in denominations of $5, $10, $25, $50, or $100 dollars using PayPal and most major credit cards.
Here is more from the announcement:
"With Steam Wallet, you can add value to your Steam account using any of the payment methods supported by Steam. Funds in your Steam Wallet may then be used to buy any item available in the Steam store on an in-game store. You can load up your Steam Wallet ahead of time, or wait until checkout. Also, different payment methods can be combined to make a single purchase.
Once you've added funds to your wallet, that money will be used by default for subsequent Steam store purchases. But if you'd prefer to reserve your wallet balance for in-game purchases of Mad Milk, Holy Mackerel and Bushwackas, no problem -- simply select another payment method during checkout. Your wallet funds will be there the next time you're ready to shop at Mann Co., or any other in-game store."