Cost of living in Jpn depends on which part of Jpn u r staying. Then what type of accomodation. What type of lifestyle u wanna have. Dorms are cheaper than renting apartments outside. Apartment rentals varies, depending on location, distance from train station, etc. But no worries. If u intend to work while studying, u shouldn't have any problems making ends meet. U're officially allowed to work 4 hrs a day, but usually, no one gives a shit if u work longer.