ATT is adding more data to its GoPhone prepaid smartphone plans without raising monthly fees in the process. If youre currently paying $60 a month for 2GB, your allotment will jump to 2.5 gigs, while those on the $40, 250MB plan will now get 500MB per month. More data is only part of the value proposition for GoPhone customers, though; the new 2.5GB plan will now offer the ability to use your phone as a WiFi hotspot.