[satch2501]

If you don't want to be charged, install boss prefs from Cydia and deactivate the edge setting. This way you will not be able to navigate the internet without a wifi connection. Wifi is free. Not edge. The jailbreak process is so you can add 3rd party application that are not supported by apple such as winterboard or summerboard. The navigation of internet should be done by wifi by the user unless they have a data plan provided by their service provider.