I couldn’t find a concise explanation anywhere on how the AT&T data pricing plans for iPad work when you run out of data. Two phone calls to AT&T have cleared it up for me. So here goes:
You sign up for a plan (e.g., $15 a month for 250 MB of data). You can purchase it for a single month or set to auto-renew.
That one-month, 250 MB plan is good until the month expires, or the 250 MB run out, whichever comes first. Examples:
* You purchase the plan on September 1. You use 210 MB by September 30. On October 1, you are charged another $15 and have a fresh 250 MB. Those new 250 MB are good until you use them all, or November 1, whichever comes first.
* You purchase the plan on September 1. On September 17, you use your 250th MB. On September 17, you are charged $15 and have a fresh 250 MB. Those 250 MB are good until you use them all or October 17, whichever comes first.
Effectively, if you run out of data, the monthly calendar resets itself for the purpose of auto-renew.
Whatever you do, do not go into the iPad in the middle of the month, when you still have data left, and “Add data or change plan.” The software will tell you that “the selected plan will start when the current plan expires.” This is correct — but you will be CHARGED for the selected plan immediately and have one month from the date of PURCHASE to use it. Another example:
* You buy a plan September 1, are low on data September 10 so add a new 250 MB plan for $15 on that date, and you actually run out of data September 17. You are charged $15 on September 10, can start using that data on September 17, and the data runs out on October 10.
If you are on auto-renew, AT&T will charge you for a new plan when you actually do run out of data. This is the preferred method:
* September 1 you purchase the plan. You run out of data September 17 and the plan renews itself. You have until October 17 to use your 250 MB.
Another thing to avoid is the “Change Plan” button in the iPad. This does not change your plan. It adds another plan on top of your current one. If you mistakenly try to “change your plan” several times, you will “stack” several data plans on top of one another. Example:
* You buy a plan September 1. On September 10, anticipating you are running out of data, you “add a plan” for 2 GB. Realizing your mistake, you “change plan” to 250 MB. You actually run out of data on September 17. What just happened is that you got charged $40 on September 10 ($25 for 2 GB plus $15 for 250 MB), and you have until October 10 to use all that data — except you can’t start using it until after you have already gone through your original 250 MB, on September 17.
I hope this is helpful. It’s a system that makes sense, albeit with some very confusing terminology on the iPad device itself. I suppose the ability to “stack” data plans exists for people who want to use more than 2 GB of data, but if you are a casual user, I’d highly recommend simply letting auto-renew take its course.