Living in Tokyo's 23-ward area is like living in Manhattan. It just doesn't make sense in having a car cost-wise, if you only drive less than once a week. Unless you need a car for professional reasons, I would suggest, as uchimizu mentioned above, to go rental. There are quite a few local rental offices in residential areas and they do rent from a half day (plus hourly rates).
You just have to know how your city is set up. Here in LA, it's really hard to get anywhere without a car. It's not impossible, but it would take 3 - 5 times more time to get anywhere, if you get anywhere at all.