Recurly Mobile — Mobile solutions for subscription businesses

Per unit pricing seems a little steep: 10¢ per transaction + 1.25% of revenue, but almost certainly cheaper than Zuora.

Recurly provides developers and merchants with fast, elegant, and secure tools for accepting mobile payments. Native mobile SDK's built specifically for Android and iOS.Hosted payment pages provide merchants with a mobile ready, PCI‑compliant approach to get up and running with minimal effort. Optimized for mobile devices, these hosted payment pages allow for easy customization to flow with your mobile site.