AT&T will let iPad owners buy a day of unlimited cellular data for $3, and it doesn't matter if your device is from Verizon, T-Mobile, or other competing wireless carriers. M3 iPad Air The cellular carrier announced Unlimited Day Pass on June 10. The service gives eligible Wi-Fi + Cellular iPads 24 hours of unlimited data on AT&T's network without requiring a monthly plan, contract, subscription, or credit check. Users can activate the service directly from the Cellular Data section of Settings