The release date for the increase of prices for AT&T's grandfathered Unlimited Data plans has struck - coming your way this February. At that time, AT&T will hike the price from $30 for an unlimited data plan - which is insane by today's standards - to $35 USD. SO it's not so terrible. For now. This keeps AT&T's prices below the hikes of their main competition, with Verizon's still at $49 a month and T-Mobile's at $45. Then there's the throttling. Always with the throttling.