I'm considering looking into getting an old iPhone 4(s) on eBay and Craigs. I know I need to look for the clean ESN and all that. My dumb phone is on its last legs with freezing issues, and I'm only 13 months into my Verizon contract. Would it be possible to (when I receive the iphone) to deactivate the old dummy phone, and use the iphone, even though I'm on contract? Would that force me to pay an ETF? I'm trying to keep this as low as possible in terms of money, and I heard you can do it online. I'm also aware of the data plans being tacked on to the phone. What's the cheapest way and is it possible?