When applying for your visa, you must prove you are able to finance your studies in Germany. You must be able to prove you can fully support yourself for at least the first 12 months. The exact living expenses depend on your lifestyle.
Further information can be found here: https://www.study-in.de/en/plan-your-studies/requirements/proof-of-financial-resources_27533.php
Here is a short list to orientate yourself: