Once you would need the service of an agency, for example to book a train ticket or whatever, before to agree for somehting, ask them which is the % or value of their services.
So, before to confirm something, bergain also about the provvision!!!!
Provvison are also on reguarding the shops, if somebody bring you there, it means that the seller will pay to theis person a commison on the things you are buying, therefore the final price will be higher! Try to avoid it!!
Its really dificult to go where you want if you take a rickshaw a taxi or if you ask to someone you want to go to a particular place ... they will always try to convince you to go to other place and if you say "no" they will go on trying to take you to the place they want telling you that that place is close, in reform or that is better to go to this other place ...
It is really hard ... they will ask you why you want to go there and not to other ...
Even if you are in a hotel ... and you ask to go to the hotel they will try to make you change your hotel ....
"Please I just want to go where I am telling you I want to go..."
Taking advantage of tourists is an art in Delhi. Be on your guard. One scam I was warned about was that taxi drivers get a commission from Hotels for taking people there, so don't be suprised if your driver tries to convince you that the hotel of your choice is full or there are Hindu/Muslim riots happening in that part of town. Be assured that taxi drivers are not that well informed. Just be persistent and insist they take you to where you want to go, and if they won't, find another.