Where I live, students pay for it, 29.40 €. It's a part of the semester fees, IIRC.

For those not familiar with how this works/worked: At most universities, a similar fee was collected from all students. That was then used to finance a regional "public transport flatrate".

N.b.: mk89 is technically not quite correct, it wasn't free (nothing in life is). It's usually bundled with the tuition/enrollment fee.

Implementation details differed per University, but for us the fee (80 or 100€, can't recall) was socialized across all students and payed together with the tuition fee; opting out was not possible (with some exceptions, like disabilities). The money went from the University administration to the AStA - the "general students council" (the executive section of the elected student self-government). The AStA then negotiated with the local public transport company/companies as well as with the Deutsche Bahn (e.g. to get access to certain inter-regional train connections - we still have cooperations with 3 or 4 nearby universities, and students somehow need to get there). Those negotiations can be a royal pita, and often the students were in a weak position.

Source: I was in the AStA (~12 people), but not involved with that task.

Thanks for the detailed answer. I guess uni students don't know or don't care so it's "for free" (in the sense it's part of the tuition fee) :)