Hi, lived in Munich for more than 30 years, was actually born there.
Munich is the most expensive place in Germany to get laid. If you get to pay less than 150 EUR consider yourself lucky.
The cheapest place in Munich with the best veriety of girls is Hansastrasse. Easily accessible by public transportation. You will find a mixture of street action and so called "Laufhaus" there. A Laufhaus is a multiple storey building where one girle occupies one room. You have to walk through the building - the girls will wait outside their room. You just have to choose...
Have fun.