"We haven't seen that in consumer devices, but with Kindle, the device constrains the data use so that Amazon can go to Sprint and negotiate a deal because they say 'my device is only sipping a little data, mostly text,'" he added. By comparison, an EV-DO data card for a laptop might cost a user $60 a month if the user also has a voice contract, Kerton noted. -Kindle to ignite trend for more consu