T-Mobile USA's (TMUS -2.6%) Operation Tablet Freedom allows customers to add tablets to their postpaid plans for free. By contrast, AT&T's (T +1.1%) Mobile Share plans and Verizon's (VZ -0.4%) More Everything plans charge $10/month for each tablet that's added to an existing data bucket.
T-Mobile is also providing customers who "bring, buy, or trade in a tablet" nearly 1.2GB/month of free data for the rest of 2014 - it'll charge $10/month for the data afterwards - and discounting 4G-capable tablets so as to price them on par with Wi-Fi-only models. A 4G 16GB iPad Air will go for $499 rather than its MSRP of $629.
Yesterday, T-Mobile unveiled its $40/month Simple Starter plan, which provides unlimited voice/text to go with a meager 200MB of data (albeit with no overages). A third pricing announcement is due tomorrow.