as it is a English speaking country.
Poland is not an English-speaking country, and most Poles do not speak English. The language there is Polish, which is not at all similar to English, and very difficult for foreigners to learn. Don't expect to speak even basic Polish for several years. Chances are very high that you will not learn more than a few common everyday expressions.
An MBA from a English-language course in Poland is unlikely to be respected much on the job market, both in Poland and elsewhere. English-language courses at Polish universities are mostly a joke, with very few exceptions.
It is just about impossible for foreign students to find part-time work in Poland. Youth employment is very high, and even Polish students have difficulty finding work. Make your plans on the very safe assumption that you will never be able to earn a single penny during your studies and stay in Poland. If you are unable to finance your studies 100% without working, then Poland is not the country for you, nor are any of the other countries in eastern and central Europe where youth employment is very high (Estonia, Latvia, Lithuania, Slovakia, Czech Republic, Hungary, Romania, Bulgaria, Greece, Macedonia, Serbia, Slovenia, Croatia, Montenegro, Albania, Italy, Spain and Portugal). Anyone who says it is easy for foreigners to find jobs in these countries is lying.
Budget at least 1500 PLN a month for a frugal student life, plus all travel, visa and permit costs. So about 2000 PLN in all. That's if you are lucky enough to get student housing. Otherwise, it will cost substantially more, up to 3500 PLN a month, or more, depending on the lifestyle you are used to.
If you can't afford to study at a good school in a richer country, you best option is to study at a top school in your own country.