I have heard that some asian exchanges don't take fees but I haven't looked into it nor does that make any sense to me. How could these exchanges therefore make enough money? From withdrawals and deposit fees?
Exactly, they make money from those gateways, most of them are charging 0.0012 for withdrawals and they are paying only 0.008 (it is a multiple output transaction)
Those are named as the hidden fees.
But it is better to do not put money in that kind of exchanges, no one knows who are the real founders of them.