I have been offered 47zl net per lesson (45 mins) in Lodz.
It's on the low side, assuming you are a qualified and experienced EFL teacher.
Is this survivable?
You'd need a good solid teaching load, say 100 hours/month, to be able to live fairly well.
You say net. Are they going to pay your health insurance? Will they help you to find a place?
When do they want you to start? Provide more details and you'll get more detailed advice.