Getting Around the City - General Info, Tokyo
It isn't that expensive compared to tother things to do in Japan/Tokyo, it is one of the fastest way to move around in Down Town of Tokyo!
Be carefull you don't catch the wrong train at the station :-)
Trains you should catch when you want to go to Yokohama, Kamakura, Hakkone, Nikko or other places around Tokyo. The are not that cheap, so watch out.
I only tried them at Kyoto, but it isn't as easy to move around by bus if you don't speak or can read Japanese...
Getting around within Tokyo is easy, If you are not familiar with the transportation there, just remember 2 things: JR and Subway. That's good enough to reach almost anywhere you want to go. You can get the route maps of JR and Subway at some of the main stations.
The JR local trains are all colour coded, which helps in making sure you are on the right one.
Yamanote line=light green
Keihin Tohoku line= light blue
and so on.