[Polar]

It's doable but why ?

Your free museum options are quite limited, this is not EUR or NA. Your admission would be $6.00+,and some parks $2-$3.

Double it to $80 and you'll have a better time, I mean in terms of options.

Subway is $2.50 - $3.50 one way, heading out to Yokohama or other regions are around $10+ each way.

Yes Tokyo can be done on the "cheap" but only after being familiar with it and by that I mean several visits by yourself not reading a guide.

I can do Manhattan quite well on $40 a day but that's because I have family to stay with when I'm there. However that's pretty limited compared to what the city has to offer