Moving to Warsaw. What salary should I ask for in banking sector?

Hello!
I have an opportunity to work in Warsaw (banking sector). What salary should I ask for to feel free with wife and 1yo kid? Please also describe average expenses for rent (incl. utilisation, can be outside center), food, cloth, etc.

with 30k PLN gross you must be fine.

@Mover: Your questions have been asked and answered a gazillion times on this forum. Use the search function and you will find many, many threads on the subject.