If you're going to have classes at Mitra and you saw how far it is, don't worry!
Despite being far from city center there are university buses that go there, for free.
There's also a facebook group for rides.
Check the map to see where the bus stops are.
University bus schedule :
8:00h - Évora-Mitra
8:45h - Évora-Mitra (Only at Porta do Raimundo stop and Residência António Gedeão stop)
12:35h - Mitra-Évora
13:15h - Mitra-Évora
14:00h - Évora-Mitra