Most Rentals are handled by the manager or owner of the rental itself. There is not enough money in leasing a property for an agent to work with someone looking for a rental. If an agent is lucky he may receive up to the first months lease payment for leasing the rental property for his client.
Let us say a tenant is looking for a 1,500 dollar a month rental. They look at 20 possible before choosing one, 20 houses * 25 mins equals 500 / 60 equals 8.33 hours. 2 days of negotiation equals about 5 hours (includes phone time, email, and consultations), that puts us at 13.33 hours.
Take the commission $1,500 minus the 2 tanks of gas (100 dollars) and the amount the broker takes (let us say 15%), that puts us around $1,175 divided by the 13.33 total work hours, puts us at 88.15 dollars an hour.
Now if we sold a house that rents for 1,500 month, we (Realtors) would typically make 4,500 dollars commission (150,000 * 3% = 4,500 dollars). Take the same time and divide into 4,500 dollars which equals $337.58 dollars an hour.
This is why there are not typically full time rental agents working exclusively for Renter's.
Check the Daily Oklahoman for leases, check the online Sunday addition, this is the least expensive means for landlords to get their property's out there in front of the potential tenants.