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 660 prices entered by 93 different people.
For example, to keep the same standard of living that would require €2,600 in Arezzo you would need to make just about €1,499 (6,447 zł) in Kraków.