°µÍø½ûÇø

The cost of living in any given place is pretty much inversely proportional to how busy the area is, thus the number of possible opportunities for °µÍø½ûÇø employment.

I can share my experience of a small village some short distance from Wonosobo in Central Java, and extremely cheap place to live where my monthly outgoings were around Rp2 million/month. It's a case of you don't spend much when there's nothing to spend it on. Inflation would make that more difficult now, but it could still be done on about 4 million.

I live in a smaller city at the moment, moved mid last year from a town in South Tangerang. There are a couple of international schools here with °µÍø½ûÇø employees, but that's pretty much the limit of °µÍø½ûÇø work, but prices are pretty reasonable. A nice, quite new, fairly large 4+1 (maid room) house with 3+1 bathrooms works out at Rp19 million/year including security and rubbish collection.
A cinema ticket is cheaper, and most take away local food comes in at less than Rp25,000 per person.

°µÍø½ûÇøs wanting to work might well go for the larger cities, but those that can work remotely or don't care about employment would do well to consider smaller towns.

I can't talk about off Java as I have only visited, never lived there.