Cost of living in Kraków (Poland) is 42% cheaper than in Arezzo (Italy)
This comparison is lacking data. It provides a decent comparison, but it is not yet reliable. It is based on 455 prices entered by 85 different people.
For example, to keep the same standard of living that would require €2,400 in Arezzo you would need to make just about €1,382 (5,949 zł) in Kraków.