Tokyo is certainly one of the world’s most expensive city for tourists, but it might not be as bad as its reputation would have you believe. Hotel bargains can be found through most of the year, especially if you book well in advance, and many or most of the things you’ll probably be coming to see are free.
Food and drink have a reputation for being outrageously expensive in Tokyo, but that’s a bit misleading. If you want to eat in upscale restaurants or hotels then you’ll pay dearly, but if you are interested in eating bowls of noodles or rice, like most of the locals do each day, then it can be done on a more modest budget. They key to surviving cheaply in Tokyo is being flexible and behaving like a local while you are there.