So if you are a foreign student on a tight budget, Poland is the cheapest European country to study in.
It's quite possible, that in spite of the reduced costs, the degree will not be worth the investment. English language programs at Polish universities tend not to have a good reputation.
The OP is a serious student, and would probably be better off studying at home in Brazil, or in another South or Central American country. They may also be eligible for scholarships to study in the States or in another English speaking country. Poland should not be at the top of this person's list, even if cost is taken into account.
I'm interested in what the OP is thinking, not what they may be thinking.
So let me repeat my questions to the OP:
What, exactly, do you want to study? And why, exactly, so you want to study it in Poland, of all places? And why not in Brazil, another South or Central American country or in an English speaking or German speaking country?