I visited Vietnam 10 years ago, it doesn't check all the boxes, but it was extremely cheap to eat, you could also find very affordable accommodation, clean, with Internet etc. A very beautiful country with the most amazing food. But as I said, that was 10 years ago, and I haven't gone back since.

In general, South-East Asia tends to be relatively cheap, safe, and there's a huge westerner community in Bali, Thailand etc, but it's a completely different culture...