Yes, just key in wrong settings such as sajlkjfalflskdjflak in Settings>General>Network>Edge or Settings>General>Cellular Data Network. Also, install Bosspref and disable Edge from it. Remember, Edge will automatically turn on and start sucking ur money when home wifi gets dc or connection lost. It sucked my RM45 within 20mins of using Maps application. Entering wrong settings will only block Edge from connecting and you will still be able to use other GPRS related services on your iphone.

Good Luck!!