t-mobile prepaid SIMs available free (get 200MB/month free for your iPad)

[Bill in NC]

And if you need a little more data Red Pocket offers a $10, 1GB/month data-only plan (running on T-Mobile).

Some people use it for their phones (VOIP calls only).

You do have to buy the SIM/microSIM/nanoSIM ($10):

http://goredpocket.com/red-pocket-4g-mob...t-sim.html

Red Pocket also is beta-testing a cheap ($20/month,) 300 minute/unlimited text/1GB data plan running on Verizon:

http://goredpocket.com/activatev

Must bring your own device (BYOD), which must be a Verizon 3G phone (not Sprint flashed to Verizon or Verizon 4G flashed to 3G)