If you run the numbers the subsidy offered by US carriers always ends up costing you more than just buying a new phone for full price with a cheaper plan. Your

If you run the numbers the subsidy offered by US carriers always ends up costing you more than just buying a new phone for full price with a cheaper plan. Your "free" iPhone isn't free if it involves (1) giving them your current one which is worth $500+ in a private sale and (2) signing up for a 3 year contract at $100+ a month.