Am I allowed to get part time job during study in Poland for MBA?

yes you are allowed to do a part time job during your study. In fact everybody has to do the job to bear the expenses overthere. because rather you will get the scholarship for your studies but for your food and stay you have to have do the job. Most of the colleges also offer you for the part time job and you are allowed to work there in your studying visa only because they know , nobody can survive there without doing work.