I read in this post that maybe it's a good idea to buy this package to go from Narita to your hotel and have get some subway credit. This page states that for ¥3500 I can get a one-way trip plus some credit.
First question: how much credit? In the upper part of the page it says it's ¥1500, but the "See how much you save!" figure says "Includes a ¥500 deposit".
Second question: I think it's not worth it for me, am I right? Using Hyperdia I found out that to go to my hotel in Chuo-Ku (Kodemmacho station) would cost only ¥1390. Am I doing something wrong? If this is right, I find it hard to believe it would be useful to someone.
Obs: for my trip back to the airport I will use the JR Pass, which will not be available when I get to Japan (bought the pass for 7 days in my 9 day trip).