edam: I have no idea exactly how much it costs per head, and it would vary enormously between universities as they all subscribe to different journals etc. There are also the costs associated with the library staff and facilities, which increase as they increase the opening hours (and students moan if they don't have long opening hours).
There is also the fact that university staff do spend an enormous time designing and preparing teaching materials/lectures. The teaching costs to the university aren't simply in 'contact time' with lecturers; it takes multiple staff time to design degree structures (and to have your courses approved by the relevant committees), to write lectures (you'd be surprised how long this takes, particularly as good university teaching should be research-led and not some generic curriculum), to prepare reading lists and handouts, to upload materials to the e-learning interface, to organise seminars, tutorials, workshops and labs, to carry out the necessary health and safety checks and paperwork, to brief any postgrads teaching on a course, to design and write the assessment materials (and have them approved by the necessary committees), to mark work, to double mark work and carry out quality assurance checks, to hold examination boards and consider appeals, to organise field trips, to have ad hoc meetings with students that aren't listed in the official course contact hours, to provide pastoral care, and so on... The university fees pay for all this and more.