To answer your question, the most cost-effective, but time-intensive, way to do it is send them out yourself. 

My method is mathematically intense. 

Rural unless you are a local investor the value isn't there to be unlocked for the intense focus it takes. 

Cold calling is time intensive and will be a mostly fruitless endeavor.

The spend is intense however the return is credible.Direct Mail - Cluster Approach.

I have an intense software program.

Your marketing will be time intensive or cash intensive...

I have only listened to about 20 minutes of one BP podcast and it happened to be Mike quarles.. in 5 minutues I could tell this guy was a pro's pro.. then I looked at the follow up.. comments on line and many thought him too car salesmen like.. in my mind those that thought him too intense or what ever they will never make it in the sales game.like I said it only took me 5 minutes to understand that this guy knows how to sell and I have been around some of the very best in my 40 years of slogging distressed RE

Depending on who can live off campus will determine if your turnover will be yearly.Management Intensive - You are not dealing with one family, but four students in a house.

This is more capital intensive but can be lucrative.