In Pictures: Windows Phone 8 - killer new features...
Windows Phone 8 will support in-app purchases, allowing you to buy additional content without having to exit the application.
Such content can include items like extra money in games, or more substantial items like magazines and newspapers. And since in-app purchases work with the Wallet hub, you'll be able to use payment apps (like the aforementioned Chase app) to pay for your purchases.
In Pictures: Windows Phone 8 - killer new features in Microsoft's latest mobile OS