The link below is useful for places to see.

There are about 200 brothels in Prague (legally, the girls are independent and pay a fee to the brothel for the use of a room).  They vary in quality and the number of girls. Some are simply two or three three-bedroom apartments with doors connecting them. There are many websites for escorts. Most of the upscale hotels have a bar where there are many ladies looking for dates.  

Rates vary greatly. Before Covid19 the rates had been dropping as Europeans were going less to Prague and more to other destinations.