I think that others (and even me) have posted this already but for some reason I can't find the thread.

I've used this twice. If you have another Suica card, run down the balance on this one to zero and then you can get your Y500 back at any JR ticket office. If you don't run down the balance to zero, they will charge you Y210 or something like that to refund the cash balance.

You could use this ticket to go as far as Kurihama, which is about Y4500 on its own! On the other hand, once you get there, you're in Kurihama, which is not too helpful if -- say -- your hotel is in Shinjuku.