If you have to sell your house - or buy one for that matter - you have to get the best price for it. Calling in a broker means you get a reduced price (if you are a seller), since he will have to be paid a brokerage.
That means one or two per cent off from the price the buyer is willing to pay you. Ditto when you buy a house. Your cost goes up by the amount of a brokerage.
Paying several thousands of rupees as brokerage merely because you were introduced to a buyer or seller may sound like a very high price to pay to many people, but before you put in a call to the neighbourhood thug to bump off your broker, here