said by KrK:
For example, I bought a new GS3 off a guy on Craigslist for $480. I have a $30+tax prepaid plan. So, assuming I only used the phone for two years and then replaced it, that would be $20 a month + service.
Or you can go say with T-Mobile Value plan where a GS3 costs $99 up front and $20 a month for 20 months for a total of $499 or...$20.79 over 24 months + the price of service. So it requires $380 less up front but $19 over the 2 year contract.
No it's not $30, but you also aren't comparing plans apples to apples. If a $30 plan suits you, that's great. But some people want or need more minutes or data.