The Japanese yen is really really cheap right now, so that is in your favour.
For years, even before the devaluation of the yen, Japan has been excellent value for accommodation, especially when compared to similar quality in Taiwan.
With booze, however, be careful. Some bars in Japan are basically private clubs, no prices indicated, girls inside, you get the picture. The larger more open izakaya places are more accessible and will have clearly marked prices. I wouldn’t recommend you try any place that does not have prices clearly indicated (not just booze but sushi places too).
Enjoy!
Guy