So i'm looking into upgrading my phone. The phone I would like is on special for a $100 off (online) and would bring down my monthly line $10. On the other hand I can get it on contract for $100 (It also goes on sale for a $1) currently. My current plan is $60/mo (single line w/ 1 GB data). Over the course of 2 years which is my best cost effective method, payment plan or 2 yr contract? Or how about buying a mint or new from a 2nd hand source? (I'm a visual person so I would like to see how you the numbers came to be)