Cost of living in Opole (Poland) is 49% 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 1,236 prices entered by 307 different people.
For example, to keep the same standard of living that would require €5,800 in Amsterdam you would need to make just about €2,962 (12,360 zł) in Opole.