I have a prepaid mostly-data SIM for $30/month via T-Mobile prepaid (http://prepaid-phones.t-mobile.com/).
Maybe we'll see more consumers move that way around Google's (rumored) November 5th phone launch.
If I were to want a plan with AT&T that offered me what I have now (450 minutes a month, 2 GB of data and unlimited texting) I'd still be out 90 USD per month whether I purchased my own device or not because AT&T doesn't do discounts for bring your own device customers (T-Mobile contract customers can get a discount for bring your own device, or at least that was the case when I was a customer with them. Knocked $20 off the price off a contract).
I'd be more than happy to purchase a phone outright and pay MUCH less per month.
My sister has an unlimited data plan, 400 minutes a month and unlimited texting for a grand total of 40 EUR in The Netherlands with T-Mobile. She doesn't talk much, but texts and iMessages a crap ton and uses about 6 GB's of data on average listening to streamable music and online radio stations. At the current exchange rate that is 50 USD. Do note that her phone is subsidized as well, also it comes unlocked so she can move carrier when her contract is up without issues.
I pay 90 USD and get only 2 GB of data a month.
How does this even make sense?
And usually their non contract plans are cheaper. They do offer another 5 GB plan for $30, but with 100 minutes / month for calls.
According to the t-mobile reps I spoke to, their refarming project will only be finished in a few cities by the end of 2012 (LA allegedly included, although in the past t-mobile reps also promised this would be done by September so YMMV). The nationwide project will take all of 2013, so don't hold your breath. I'm about 30 days away from dumping them and going with Straight Talk.
$45 price point seems unbelievable.