Customers not on a contract and willing to avoid AT&T, Verizon and Sprint can avoid quite a bit of fees. E.g. T-mobile has a $30 plan for 100 minutes, 5GB of 3G (and EDGE after that), and unlimited SMSs. The 100 minutes is problematic, but I use Google Voice so I can just use my computer for phone calls at home. And at $0.10 per minute overages, it's still cheaper than any of the contract plans.
There are also other carriers in the US with cheap plans if you're willing to shop around.
This by itself would now be difficult for me. I have an unlimited (grandfathered) data plan from Verizon with 4G. I know several people who have it now, and they would never go back to 3G. Any MVNO that Google creates is going to have to support the latest technology.
There have been rumors of Apple creating their own cellular company - now would be the right time. Create a 4G-only cellular company that provides unlimited (HD) voice, texts, and data for one flat rate, Apple-style, with no contracts.
It's actually T-Mobile's HSPA+ network, which is somewhere between 3G and 4G. In theory, it should go up to 45Mbit down -- I've never gotten more than 10, but that's still plenty for my usage.
There are also other carriers in the US with cheap plans if you're willing to shop around.