hi,when you rent apartment in japan, you have to find guarantor .guarantor is person who live in japan and have source of income in japan.can you find them ? if you can not find them ,you have to hire guarantor company.but they charge very high fee.cuz, when you do not pay your rent, guarator company have to pay rent on behalf of you.their job is risky so, they charge high fee.
but if you have some amount of money , why do not buy apartment ? If you are willing to buy apartment out of center of tokyo,you can buy it rather cheaply .especially, in saitama or chiba prefecture.there are enough transportation in japan, so you can go to your school or office by train.and moreover if you want to buy it cheaply, it is better of you to buy foreclosed properties in japan.you can buy it very cheaply.i know that one foreigner bought house and land at the price of only 1500000 yen.you can find their blog site when you search for "foreclosed , japan, akiyama".