Originally Posted by PoundSand
if you want att and are willing to buy your own phone, look at straight talk prepaid. $45/month, and you can chose tmobile or att as the network. cheaper than using att's own prepaid plan. ;D
We have a winner!
(Second) best deal around if you buy your own phone. #1 is T-Mobile's $30 100min/unlimited msg/5GB data on an Android phone with a VoIP app, but OP says no to T-Mo, so Straight Talk on AT&T's network is the answer.
Forget the CDMA carriers (Verizon and Sprint) and all their MVNOs (Virgin, Boost, etc etc). Too much bullshit if you want to switch. With the GSM carriers (T-Mobile and AT&T), if your phone is unlocked, you can switch carriers whenever you want with a new SIM, though a number of smartphones only support one or the other's 3G/4G frequencies. Among others, Google's phones are 5-band, though after last week's Nexus 4 launch fiasco, it might be a while before you can get one.
Also worth noting if you've got one T-Mobile dead spot is that many T-Mobile phones can make calls over wifi. With the 'normal' plans, wifi calls are free, but on prepaid they do count against your minutes. SMS and MMS work over wifi too, though you can't switch from wifi to the cellular network mid-call unless you're on a BlackBerry.