The break down:
AT&T pay-as-you-go customers will need to pay credits towards the days they expect service. Basically pay $3 up front for every day you want to make or receive calls on your GoPhone. Each day you have paid for in advance you'll receieve unlimited voice service for the entire day including no roaming or long distance fees on the company’s national wireless network.
If users do not make or receive any calls during the day then there will be no fees collocted from your account and it will rollover.
Customers on the new GoPhone Unlimited Calling plan won't be limited to calls only. AT&T said users will be able to use text messaging and data service at the same pay per use rates as all other GoPhone Pay As You Go plans, or customers can add messaging or data packages.
For customers who primarily call other AT&T mobile subscribers, AT&T also offers an Unlimited Mobile-to-Mobile plan, which provides unlimited calling to and from all 78 million AT&T wireless customers, and $0.10 for all other calls, for $1 a day.The new AT&T GoPhone packages, which include a new device (prices vary by device selected) plus $15 airtime credit. You can purchase them online, at AT&T stores or other retail locations including Wal-Mart. Current GoPhone customers will be able to switch to the unlimited calling plan by calling 611 from their handset, or 800-901-9878 from a landline phone. Feature packages such as unlimited text messaging for $19.99 can be added by choosing the option 'Buy Features.' More information will be available at www.att.com/gophone.
Source: ATT Press Release