day pass is overkill for most people, unless you are running around town nonstop. day pass for subway only is 710 yen for one company and 730 yen for another company - there 2 subway companies served the city and the day pass is not interchangeable. The best approach is just to buy the subway tickets as needed, or use a cash card which starts at 1000 Yen. Again, it cannot be interchangeable between different companies.

the subway fare is usually a bit more expensive than the railway fare but of course subway is a lot faster as railway in tokyo is basically a circular line and a central crossing line, while subway can criss-cross the city thru changing lines.

however, the subway tickets are no more expensive than any major U.S. cities, such as NYC, Chicago or D.C.

from what i remember, the highest fare between stations is 290 Yen, and lowest 160 Yen, with most common fare at 190 yen. i believe i paid 190 yen from Ginza to Roppingi. Roppingi location is only served by subway.

also there are 2 private railway services other than JR. JR pass do not work on the private lines. some areas near ebisu are served by private lines only.