Students only have to pay the semester fees (contribution to administration costs, student services, the semester ticket, AStA) at the University of Kassel or the Kunsthochschule Kassel. No tuition fees are charged. The semester fees must be paid when enrolling and thereafter each time that you reregister for the following semester. You also have to pay for the cost of living like your rent, food, health insurance, books etc. This may add up to a figure of between EUR 600 and EUR 1000, depending on your place of residence and your needs.
More information on the semester fees.