So I bought an iphone 3g 16gb from a friend for $50 hoping to use it on T-mobile. So far I've jailbroken and ran ultrasn0w(which appears to have worked.) I'm ready to put the SIM from my t-mobile dumbphone in, I just need to know 2 things. 1. Will I be charged for data if 3g is off and cellular data is switched to off? My family plan is ONLY calling and texting, so I CANNOT use any data! I plan on using wifi only. 2. Must anything else be done for calling and texting to work? Thanks in advance!