Budget for Tokyo University Exchange Student (NO rent)

hey all! i am going to tokyo for exchange this june and was wondering what a good budget would be without rent and utilities (i have already paid for them). i am from hong kong so i was thinking a budget of 90000JPY per month without rent and utilities would be okay? also, is hsbc widely available in tokyo? i am quite lost, please help me out!

thanks!

by dumplingmala