[Sangetsu]

First, where are you from? Japan has a working-holiday agreement with many countries which allows one to get a 6 month to 1 year visa, and enables one to work part-time. Unfortunately, there is no such agreement between Japan and America.

Japanese don't really want to hire short-term, temporary workers without valid visas. There are enough legally eligible people available right now who are looking for work, so your prospects are not great.

There are a few musically-inclined foreigners who often perform in parks or near stations for a little ready cash, but the amount of money they make is underwhelming.

If you are careful, a 1 or 2 month trip to Japan needn't be expensive. Quite a few people seem to get by on $10 a day without any problem. Your best bet right now is to get whatever extra part-time work is available where you are and save it up for your trip.