German state universities currently do not charge student fees, but a contribution about 300 Euros per semester.
When it comes to living costs, every student is obliged to cover his/her own health insurance (about 100 Euros per month) for his/her rent for an apartment/room/flat, daily costs for food/hygiene/social life. Depending on housing (dormitory, shared flat, apartment), the living costs in Bochum amount to about 700 Euros per month minimum.
Information on Living Costs for International Students
Living Costs widely differ from country to country, and even between regions of one country. Ruhr Universität Bochum's international office provides information for international students on living costs in Germany, and especially in Bochum.