If you need an app that will help you to monitor your local cell/wifi usage, then you need to try the Quota app. The app even allows you to set up alerts to notify you when over ideal or % usage. The app is completely free for one account with no advertising.
– Monitors you local cell/wifi usage
– Setup alerts to notify you when over ideal or % usage
– Monitors multiple ISP/Mobile/Travel/Tolls
– Powered by QuotaXML with access to 100’s providers worldwide
– User created providers are supported via the free developers kit
– Dropbox sync support
– Widget support
– PIN security
You can download Quota from Google Play here.
You can read how to use the Quota app here.