So here is my situation guys; I am a college student and currently have iphone 4 whose power and home button is all whacked up, I am using assistive touch feature on it to hold me till September 10. I am currently on walmart's $30 prepaid tmobile plan. I really really want the iphone 5S, 16 gigs as soon as it comes out. So here is my question, should I 1) Buy At&t version on release date, use it for more than 14 days, get the service cancelled, pay ETF and then use my tmobile sim. 2) Or should I just buy the factory unlocked iphone right away and use my tmobile sim in it. Which one will save me money? I think buying At&T version would save me $100 but not really sure. Thanks for your help!!