Here's an interesting article. It's the US price breakdown for the Tab across different carriers.

http://www.pcmag.com/article2/0,2817,2372723,00.asp

What's interesting is that for 2 years 1GB/mo sprint offers the best price by a LONG run. In fact, if you plan to use data at all, it's worth consideration.

Of course in 2 years the Tab is going to be looking extremely old.