In-App Purchases are extremely common in mobile apps and games these days. As an AT&T customer, I have the option of paying for Windows Phone IAPs by credit card, carrier billing, or Microsoft account. People with different carriers or living in other countries might not have access to those same payment methods. And you normally couldn’t use carrier billing for Windows 8 purchases. Mobile payment provider Fortumo allows app developers to easily integrate carrier billing for IAPs into both Windows Phone and Windows 8/RT apps and games. Fortumo is so serious about getting Windows developers on-board that they’ve just launched a fund to pay advances to successful developers for integrating Fortumo payments into their apps. How successful does a developer need to be in order to get the funding?