Everywhere in Southeast Asia - Thailand, Malaysia, Philipiness, Indonesia, Vietnam plus you have great cuisine and no need to worry about cold weather much.
Smaller towns in Poland, Czechia, Slovakia, Hungary should be also no problem, just forget about top 5 cities in each country, in Bulgaria/Romania maybe even bigger cities, just not capitals.
I would more worry about long term visa situation than about cost.
You also didn't define "living", one thing is sit at home most of the time, cook for yourself and just hang around city without travel, other thing is going to pubs 3 times a week, travelling on weekends etc. Entirely different budgets.
Smaller towns in Poland, Czechia, Slovakia, Hungary should be also no problem, just forget about top 5 cities in each country, in Bulgaria/Romania maybe even bigger cities, just not capitals.
I would more worry about long term visa situation than about cost.
You also didn't define "living", one thing is sit at home most of the time, cook for yourself and just hang around city without travel, other thing is going to pubs 3 times a week, travelling on weekends etc. Entirely different budgets.