Sony Ericsson S710a

I was wonderin about the amazon s710a, what i mean is if we order off of there websit will the phone still be the same and come in the cingular box and everything, i want to add a line to my moms plan so can i do that from amazon and also a guy who rated this phone on the user reviews said this phone came with everything so will ordering off of amazon give me the same thing, i love this phone and i would gladly pay 400 on it but the way my mom is i need to get it a little cheaper then that .