The reason I'm asking is because its my dream to live in Japan teaching English. I don't want to go and come back in 3 or so years, I would prefer such a move to be permanent. Also, info on money, as in how much it costs to live comfortably in Japan, is appreciated.

1.) No, I don't want to move to Japan because I'm some anime otaku. Out of all the cultures and languages I've studied, this one has interested me the most.
2.) Yes, I know Japan is not an immigrant country and that citizenship or permanent resident status is hard to come by.
3.) Yes, I realize I should learn Japanese. Duh. Currently working on it.

Thanks for the answers :)
You have some pretty good advice. :) Trust me, If I don't like it after the first few years, I'll return home. I'm not one to put up with something I don't like. I'm just thinking hypothetically, assuming I like enjoy Japan.

Well, close to 20 years with a break a few years back.
Quite honestly, you really can't say whether you will want to stay one year, much less 10, until you have come over and tried it. Some people love the country for years, and then come to dislike it as their situation changes. What I mean is, it can be great fun for a single guy, but more difficult for someone who has children and business to take care of.

That said, the best thing you can do is come over for a year or two. If you like, stay. In most cases, people move on to jobs that are more interesting, and better paying, than teaching English - especially if they can speak Japanese.

Your basic English teaching job might pay 250,000 yen per month, and you can pick up extra money teaching on the side. That won't get you very far, especially in Tokyo, but it will be enough to get you set up. You can take it from there.

Costs are coming down a bit, and you can live quite cheaply. The main thing is to get a place to shower and sleep, and then build on your life from that. Almost any job will cover those basic needs.

Lastly....give it time! Just as you shouldn't decide on 10 years before even visiting, you shouldn't make any rash decisions in your first couple of years either. There's plenty to like and dislike - and they often go hand in hand. If you accept that it's not all sweetness and roses, and that some things you dislike also have positive effects, then you'll do fine.

me too! i like manga, which got me hooked on the language. Japanese rocks!!

anyway, I haven't lived in Japan at all, to answer the actual question.

I have been here for 5 and a half years and had every desire to stay longer but my partner is now pregnant so we are going to go back to NZ to start a family....but I digress....

In regards to money, it depends on where you want to live....for example...
A very small apartment in Tokyo can cost more than 80,000yen/month whereas in Shimane and Fukui (the 2 prefectures I have lived in) 40,000yen can get you a much larger room.

I think a wage of 250,000/month will allow you to live but maybe not have all that much money to save/play with. Somewhere around the 300,000/month mark will be a good wage.

Good luck in Japan, I have loved my time here and hope to keep the connections I have made with the people and language.

With the Language....make sure you have Hiragan, Katakana and very basic conversation down before you get here and you should find picking up conversation not too difficult!!

ganbatte!!

you should learn JAPANESE.
There are expats who have lived here 20 years plus & all they can say are words like
sugoi , ganbatte , & kawaii
its very stupid