It's great that you chose Microbiology as a future course. Since you are planning for postgraduate degree if you are having a B.Sc degree in Microbiology then your chances will be high, there are many colleges offering Microbiology course based on your percentage of marks in Bachelor's degree. But there exists other colleges too where you need to give entrance exams to get admission. Like GMAT or GATE. In future your career prospectives can be

Clinical Microbiologist

Industrial Microbiologist

Environment Microbiologist

Virologist etc.

Fee structure depends on different institutions, government colleges has less structure than private ones. But your future is very bright.

Good luck!! Know more about your course

https://www.careers360.com/courses/microbiology-course