It does not cost anything to go to university for Swedish citizens. Nowadays there is a tuition fee for people outside of EU/EEA/Switzerland but there are also scholarships for foreign students that want to attend a master programme (at least at Stockholm university).

In Sweden, for Swedes, Education (Primary, Secondary, High school and University is free of charge (Some private schools excluded...), but you have to pay for books etc.. It used to be free for foreign guest students swell, but now I believe that they have to pay for their studies since last year or something like that.