My wife and I decided to de-clutter our home a bit and had a garage sale today. We put a $20 ad in the Trib and a free post on Craigslist. We also put out directional signs on a couple street corners.
The response was tremendous. Had 97%+ of the items sold within 2 hours. In the informal survey I took, most everyone came because of the directional signs. I only found one person that came because of the Tribune ad (looking for something I listed in there) and no one I talked to had found about our sale from Craigslist.
This is similar to Open Houses. Most people that come to Open Houses are just driving around the area and see the signs.