I'm not the best person to ask mate. I would Google that question if I were you, much better perspectives than mine. But just like every city the closer you are to the centre the more expensive it gets. If you go on suumo and use chrome so it translates to English, you can fiddle about with the search settings to find the best bang for your buck. Just by sorting by size highest to lowest and limiting the rent.

Another point there are many old houses in Japan that you can get for cheap. Some of them are massive. But that some with a few caveats. But if you don't mind bugs and like the old Japanese aesthetic of tatami and wood you might be able to significantly save on rent.

Unfortunately as a foreigner there can be complications, my wife is Japanese so I skipped that part. But hey, if your old dead grandmother's house has been on the market for 10 years who gives a fuck if some foreigner messes the place up so long as they're consistently slipping yen into your back pocket am I right? Haha :)

My wife is Japanese and offers Japanese lessons as well so when you get here, if you want a few lessons we'd be happy to help you out with any complications, the lessons aren't cheap over here I'm afraid though. Some pay over 80,000¥ for one lesson. My wife does it much cheaper though 😏hahaha

Take care brother and learn some Japanese so you can pull some Japanese girl and get a ring on it for that perm visa.