The costs for public health insurance is 14-15% of your income with a lower income bound of 1061,67€ and an upper bound of 4687,50€. Thus the minimum cost is 148€ and the maximum is 656€ (for the exact same service).

In addition you need to pay 3% Pflegeversicherung (nursing care insurance).

https://www.krankenkassen.de/gesetzliche-krankenkassen/krank...