Be very careful about your data plan. This is what happened to me today.
I opened up my credit card statement and found that AT&T had charged me for two data plans on my pad. I originally had the unlimited one and then the next month I decided to change to the 250 MB to see if it was all I needed. I signed up on June 4th which would expire on July 4th. I went in on July 3rd and changed it . I then received a email from AT&T on the 2nd saying they were auto debiting my credit card. I immediately got on the phone and told the rep that I did not want the unlimited plan and she said that it was okay because the charge had been denied when I put in for the new plan.
I just called AT&T to have them credit me back the 29.99 and was told that because the charge is prepaid, I could not get it back. What a bunch of bull. I will not subscribe again. I have modified my Palm Pre to be a hotspot so that is what I will be using from now on. I guess I could have gone with the wifi only pad had I known this was going to be a problem. This is a word to the wise to remember to change or cancel your plan at least 2 days before it is going to expire.