[stumm]

This not true for all carriers. T-mobile has cheaper non-contract plans.

No-contract is 50 dollars for unlimited everything ($70 if you want 4G): http://prepaid-phones.t-mobile.com/monthly-4g-plans

With a contract it is 90 dollars for unlimited everything (which I believe is roughly standard across the industry): http://www.t-mobile.com/shop/plans/individual-plans.aspx

[Steko]

Yes all 3 people note that you can get a cheaper contract on T-Mobile. However the 500 lb gorilla none of them mention is that T-Mobile's network really sucks:

http://opensignal.com/coverage-maps/US/San%20Francisco/

T-Mobile in San Francisco makes AT&T's network look good and it's a shadow of Verizon everywhere.