Cost of living in Orsk (Russia) is 39% more expensive than in Zrenjanin (Serbia)
This comparison is lacking data. It provides a decent comparison, but it is not yet reliable. It is based on less than 10 prices entered by less than 5 different people.
For example, you would need at least 102,622 Дин. (руб 65,261) in Orsk to maintain the same standard of living that you can have with 74,000 Дин. in Zrenjanin.