Hard to know if this is the carrier's fault, or Microsoft's for making a phone that consumes enough bandwidth etc. that carriers need to charge high rates to recoup their costs, without providing enough value to the end customer to justify the rates from his/her perspective.
If Microsoft made something that just did messaging and social tools based on messaging until it hit a WiFi spot, they could've gotten their intended market. Make something that can dial your phone over Bluetooth or dial it Google Voice style by sending a recognition code based on Elliptic Curve Cryptography to a central server. Charge the carrier cost for the SMS messaging used as infrastructure and make money on ads.
