Say that I bought an iPhone off of Craigslist or eBay and I don't want to update my plan for iPhone (Because I can't afford it! ) will it work? Right now I have an LG Vu with just regular Phone calling and Texting. Will the SIM Card out of my Vu work with the iPhone? I won't use the Internet or Apps that need internet unless I have WiFi. So, has anyone done this before? Thanks!