A (s)imple, (l)ightweight, network traffic counter widget. It displays network traffic without the need of any permission. No ads. 100% fat free. Only 60 Kb small so it won't eat up your device storage space. It updates only once per minute to extend your battery life. You can reset the counters by pressing the "reset" button. The button on the right switches between 3 different traffic counter views(cellular data traffic, wifi/wlan traffic, total traffic). If you find any errors please write me an email. Accuracy has to be tested over time. Don't take it for sure that the displayed value is 100% correct.
Does not work on all phones.
This is a widget so you need to drop it on your homescreen it is not an app.

Open source GNU GPL 3.0
Source code:
http://code.google.com/p/slw-battery-widget/