How much does it cost to live in a non-metro area? Also, what all do I need to keep in mind when going there for an internship.

I assume this question has been asked a lot and even now it is. But I was still confused even after watching various videos about it so I thought of making this post.

I will graduate next year and in my home country India I am getting a starting salary of about 85,000 yen but the company in Japan said 220,000 yen. But here in India since I'll be living with my family I wouldn't have to worry about rent, or groceries as much and would instead be able to support them. As for Japan I have heard mixed things, with our sensei obviously saying that it is a great amount, some seniors saying that it is decent, while others even saying that they managed to save a lot.

So, yeah, I am confused if this opportunity is good or not (solely speaking monetarily) and wether I'll struggle in Japan.

 Edit-1

The company and any other will exclusively be from Ibaraki prefecture because of the university's tie up with prefectural government. And they often mention that the cost of living there is like 3 times as low.

 Edit-2

Also, is it true that I'll be stuck in the same company for decades? Here in India everyone I know has changed their company every few years or so for better opportunities. And we were specifically told by the labour minister that this is very frowned upon. But also that it's cool.