I probably should post this somewhere else, but my question kind of fits in this thread for those thinking of switching or for a 2nd phone as I am thinking.

So I am thinking of buying a 1st iPhone off of CL as my 2nd or "fun" phone. I am a US customer on the T-Mobile network. If I bought one that was already ready to go for T-Mobile, what data plan would I have to purchase through T-Mobile to get email and internet?