This realtor magazine had more than 100 realtors in my area. The best part was that all of there email were listed (all realtors check there emails by the minute) and at least half of these guys did not have a website! These guys are paying a pretty penny to be in these magazines to have there properties listed so you know that they are willing to pay for good marketing.
I'm sure you can pick any service to market to these guys and have great success with this method
And the best part is that it is a free source for great leads!