What is the cheapest unlimited plan for iPhone 4S?

What provider would have the cheapest plan for this phone? (AT&T, T-Mobile, Verizon, etc… ). Or unlimited data and text, it doesn't really matter about the talk.

That would be Virgin Mobile. $35 plan includes 300 minutes talk time, unlimited text and 2.5GB of data internet.

Feel free to customize a plan online, one that better serves your needs.

http://superbutilities.shopacnrep.com/wireless/index.aspx