Postpaid plans are the problem here. They're something of a tax upon people who can't do math if you have a subsidized phone; they're terrible if you bring your own phone.
If you bring your own phone, you want to be looking at the prepaid arrangements. AT&T has considerably cheaper prepaid plans than their postpaid plans (I think it was like $40 cheaper when I looked?). T-Mobile's prepaid plans are even cheaper; I pay $30/month for 100 voice minutes ($0.10/minute overage, which I've hit a couple times), unlimited data (speed-throttled at 5GB), and unlimited texts.
I paid $350 for my Galaxy Nexus and ditched my $90/month AT&T postpaid plan for the $30/month T-Mobile prepaid plan, and the delta in plan costs paid off the cost of the phone (over a carrier subsidy) in about four months.
T-mobile's postpaid "value" plans can also be a good deal (no phone subsidy, but yes contract/ETF). We just moved from the prepaid $30/month/line plan to a family value plan, because we could get 5 lines for <$20/month/line (unlimited talk/text on all lines, 200mb data on two lines).
If you bring your own phone, you want to be looking at the prepaid arrangements. AT&T has considerably cheaper prepaid plans than their postpaid plans (I think it was like $40 cheaper when I looked?). T-Mobile's prepaid plans are even cheaper; I pay $30/month for 100 voice minutes ($0.10/minute overage, which I've hit a couple times), unlimited data (speed-throttled at 5GB), and unlimited texts.
I paid $350 for my Galaxy Nexus and ditched my $90/month AT&T postpaid plan for the $30/month T-Mobile prepaid plan, and the delta in plan costs paid off the cost of the phone (over a carrier subsidy) in about four months.