Hi there! I have a lead on a used iphone and I have some questions. I currently have a sony walkman (barf) that I just got and want to take back. Can I put the SIM from that phone into the iphone? Will that prevent me from having to buy the data package each month? Is there any way around this? I really don't want to pay $20 a month for EDGE, I am usually around wifi and when I'm not I can live..... Thanks!