[Nyororin]

There are two different types of re-entry permits. The single use type, and the multiple use type. The single one ends after (obviously) a single use. The multiple use one only lasts a year, no matter what type of visa you have. (A 3 year visa? Permanent residency? Oh well. You`ll need a new one every year.)
I have never had a multiple entry one. I`ve never left the country 3 or more times in a single year. And if you don`t, then it`s a total waste of money. Twice, and you`d might as well have gotten the single use one, as it costs the same anyway.
Now, if the multiple entry lasted the entire length of a visa... ie. forever with the permanent residency one, etc.... That would be nice. But it doesn`t.

I also want to correct what I said about the permanent residency. You can technically get it if you`ve lived in Japan continuously for 5 of more years. *Technically*, as in that`s what you need for the application. That doesn`t mean they`ll grant it to you - although I have heard of it happening. As for after you`re married - if you`ve been married for 5 years, even if most of that time was spent outside of Japan, you can apply.

You never get it automatically, even if you`ve been married for 20 years and have 10 kids. You HAVE to apply just like everyone else.

Also - more in regards to living costs. It is very possible to live on very little... However, you do need to keep in mind that you can`t START with very little. Apartments require deposits, utilities require hook-up fees (the phone line being the worst of it), etc etc. You can`t walk up with 100,000 and expect to survive the first month if you don`t already have all of this lined up.