Zebbo have developed a cool service for app developers so they can better monetize their apps. The app using SMS and carrier relationships to provide developers with a means to offer carrier billing for their apps. The downside is that for certain carriers, the website will take upwards of a 50% commission on the sale. This is probably because the fees that carriers are charging are so significant. In any case, the large commission may be offset by the fact that you can reach users who would otherwise not purchase with a credit card or PayPal.