With just a credit card, no contract required, you can buy a SIM for $2.75 and $1/month gets you 750k of data. You can turn SIMs on and off month to month. You have to buy 10 SIMs to get started but they are having a promotion right now to get 10 SIMs for the price of one.
I have no connection to either Seeed Studio or Aeris other than being a happy customer of both
http://www.seeedstudio.com/depot/Seeeduino-GPRS-p-1909.html
What about a SIM and data plan you ask? Head over to:
http://neo.aeris.com/
With just a credit card, no contract required, you can buy a SIM for $2.75 and $1/month gets you 750k of data. You can turn SIMs on and off month to month. You have to buy 10 SIMs to get started but they are having a promotion right now to get 10 SIMs for the price of one.
I have no connection to either Seeed Studio or Aeris other than being a happy customer of both