T-Mobile is launching a big bid to get people buying tablets on its network. Beginning this weekend, itll be offering 1 GB of data service for free through the end of the year to anyone who subscribes to a T-Mobile postpaid voice plan. T-Mobile is obviously hoping that once people start getting data to their tablet they wont want to stop, and its structuring the deal such that it might not seem like much of a change when they have to start paying. While the 1GB is effectively offered for free, T-Mobile is technically giving subscribers $10 off of both the $20 data plan and their voice plan.