NetCounter is described as 'simple network traffic counter for EDGE/3G and Wi-Fi. It shows your data usage. Data are persistent and you can set the counters (monthly, last 7 days, today, etc) you need' and is an app in the Network & Admin category. There are nine alternatives to NetCounter for Android, iPhone, iPad, Apple Watch and Online / Web-based. The best alternative is 3G Watchdog, which is free. Other great apps like NetCounter are Call Meter 3G (Free), My Data Manager (Free), Free Hit Counter .Net (Free) and Credit Usage (Freemium).
"Credit Usage" is a convenient application for Android mobile handsets which keeps track of users credit usage (voice / sms / mms / 3G data), and so helps to prevent inadvertent excess usage of ones credit allowance.