[Nyororin]

I don`t know the official minimum wage, but the cheapest I ever spot around here it 650/hr.

But most people I know live on a salary, which is really the norm in Japan. Hourly pay is very part-time. If you have a full time job, there is no reason not to be a 正社員 and be paid a salary.
Salary varies a lot based on your line of work, age, qualifications, length of employment, etc. I`d say a common *starting* wage is 190,000/month before taxes.

Living costs in the city can be incredibly high. In the countryside, they can be quite low... However there is no work available in the countryside. Some people commute, but a 2 hour commute each way is not something you want to do each day if you can avoid it.

In Nagoya (Which is drastically cheaper than Tokyo, but still a very big city) the average one room is around 60,000/month, and for a nice 2 bedroom, it would be around 90,000/month. There are cheaper (but some are very old, decrepit, etc), and there are more expensive - very nice places run up to around 150,000/month. The bigger the apartment, the higher it goes.
It really depends on where in the city, how convenient it is to public transportation, etc. There really are no bad parts of town, so that has very little effect on the pricing.

As a side note - our friend (Japanese) in Tokyo makes 300,000/month before taxes and pays 180,000 for a 1 bedroom apartment inside the city. Apparently that was they cheapest he could find within 1 hour`s commute of his work. After taxes, rent, utilities and sparse food is paid for, he has like nothing left.
I really can`t understand at all why everyone wants to live in Tokyo. No matter how much you make, you end up living on a shoestring budget.