You could do a group search and see what comes up. I'm not sure with the new Facebook graph system if groups and businesses only pull up in your specific area, if they are described as serving a specific area.
I did a search for "Find all groups named "fresno yard sale"" and the following link is what pulled up..
https://www.facebook.com/search/str/fresno%20yard%20sale/groups-namedOf course, i don't know what town you live in, or what semi major area you live near.. but for Fresno, there are quite a few groups that sell items online through Facebook.
If there are no groups like this in your area, I strongly suggest starting one! Create the group, the rules, put up 30 or so items on the group page, and advertise your page on busy groups in your specific area.. I make 2-3 sales a week through these pages, but it has brought in 100+ customers into the shop in the last month. About half of those customers bought something that wasn't on the group page.