Some of the schools you found may have seemed very attractive. Now is a good time to ask additional questions. A handful of examples:

"A field lesson is how many minutes (50, 60 or 90) with you?
The trial lesson is free?
Is the cost of the mandatory health certificate included in the package price?
Is the cost of the theory exam with a certified translator included in the package price?
Is there anything else I need to know about the cost of a driver's license? For example, €40 at the candidate's expense for picking up the right from the municipality, etc."

In Poolster for you, I broke it down to atoms.

Sample lesson (90 minutes):
Free of charge (with any package, otherwise €50)
Lesson 60 min:
€55,00
Practical exam:
€270 PRICE INCLUDES ONE HOUR OF DRIVING BEFORE THE EXAM
Practical exam, orientation (TTT):
€220 PRICE INCLUDES ONE HOUR OF DRIVING BEFORE THE EXAM
Theoretical exam j. Dutch:
€36,25
Theoretical exam j. Dutch Extra Time:
€46.55 (including an allowance of €10.50, If you have a dyslexia certificate, you will receive it back within 14 hundred days)
Theoretical exam j. English:
€41,75
Theoretical exam j. Polish:
€280
Theory book:
€32,50
Theory book with online tests:
€76.50 (textbook plus 15 hours of practice with online tests in Polish (25 realistic exams)