I have ATT and I pay about 80 a month. I'm at 2gb's/month and that's enough since I use WiFi at home and at work. I do use Pandora, Spotify, Netflix, Youtube, etc on it with no problems on 3G, there's no 4G in my area for some forking reason.
I can't recommend the Nitro or Skyrocket, since I don't know anything about them... but you can't go wrong with anything Tegra 2+.
