Thank you to everyone for all the helpful information you have provided me thus far.
We will be in Tokyo for 5 days and will probably be using the subway system extensively to get around. I have read about the PASMO and Suica cards, but I am a little confused about the differences and advantages of each one. We will be going to Kamakura for a day, using the Narita Express to get to Tokyo, and, as I've stated, using the subway system to get around. Which card would be our best choice for this? Do we purchase these cards at the Narita JR station and do they refund money leftover on the card?
We have a railpass, but will not be activating it until our final day in Tokyo. Any information will be greatly appreciated.