Parse
Parse handles everything you need to store data securely and efficiently in the cloud. Store basic data types, locations, photos, and query across them in just a few lines of code.
Pricing: Free < 15 million request a month otherwise 199$ month
https://parse.com/products/data
Stackmob
The StackMob platform lets you build applications using data from any cloud or behind the firewall, so you can get to market faster than ever. The platform has the features to build any application, but the platform is not an island; we’ve engineered it to work with countless third party services and data sources.
Pricing: Free, pro plans with extra features
https://www.stackmob.com/product/
Kinvey
User management: Add any number of users, using the authentication systems of your choice. You can use Kinvey, Facebook, Twitter, Google, LinkedIn and any other OAuth2 authentication provider.
Data storage: Instantly and securely sync data between your app and Kinvey backend. Your data is stored on the device or browser, ensuring content remains available even when your user is offline.
Pricing: Free to start, pay per 100(0) users. Upgrade for extra storage space or "free users"