A free app for Android, by Roy Solberg.
Data Usage Manager & Monitor is a free utility for monitoring and managing your mobile data usage. It allows you to keep an eye on the type of information your phone is accessing, and to restrict its use to the necessary minimum.
The application can be used on Android devices that run on the Android operating system. It is a free, useful tool that can help you to manage your usage without going over your limit.
Data Usage Manager & Monitor can be used as a data management tracker and a network monitoring tool. It can also be used to switch to the Wi-Fi or mobile network of your choice.