Cost of living in Opole (Poland) is 52% cheaper than in Amsterdam (Netherlands)
This comparison is lacking data. It provides a decent comparison, but it is not yet reliable. It is based on 1,324 prices entered by 331 different people.
For example, to keep the same standard of living that would require €5,100 in Amsterdam you would need to make just about €2,439 (10,518 zł) in Opole.