said by 93388818:
and with the exception of December 2009, all of my usage was under 500 MB. Same with my wife, except hers, on her iPhone 3G was all under 400 MB.
To me, this plan is going to save me $10 a month.
That's paltry, and you'll likely end up paying it all back and more in that one month you or your wife accidentally conduct some heavy usage.