With your student ID from Saarland University, you can use the public transport in the whole Saarland (province in Germany) for free. This includes the buses, the Saarbahn (tramway) as well as the trains.
Don’t forget to always carry your student ID with you, you have to show it anytime you enter the bus.
Bus lines going to university Campus: 101, 102, 109, 136, 138, 163, 150, 170
Bus line going to Dudweiler: 102
Tipp: Since March 2020, the public transport in Luxemburg is free, thus you can go there for free from Saarbrücken with your student ID.