In Qatar I visited a lot of houses - villa - flats - stand alone (in 2004 and 2009) and I was never requested to pay a commission to the agent. The ads were on local newspapers.

First time I saw commission (in Qatar) was on QL.

But I would say that if you find the place of your dream at a good price (always negotiate the rent) not to take it because you have to pay a commission would not be very reasonable.