I joined my town's Facebook virtual garage sale last fall when I was looking for a bike for Little Man at a friend's recommendation. I posted an ISO (in search of) listing and quickly received an answer from a Mom who had a like new boys bike. Picked it up next day for $20.
I forgot about the site for a while but started checking it out again after the holidays. Since then I've gotten a black Coach purse, a bunch of Legos and lots of books for my kids for 20-30% the usual cost. I admit I check it a bit obsessively now.
If you're wondering why not just use Craig'slist or ebay - this is easier. Instead of having to search using keywords for your item of interest, within your geographical location, you just scroll through the newsfeed and check out/respond to the things you are interested in.
The admins set the tone and in some cases let anything go. The ones on the site I follow have a long list of rules but that protects everyone. Craigslist doesn't do that. Also I hear all sorts of horror stories about Craigslist. At this point most of the sellers I have bought from have left the items on their doorstep for me and I just put the money in the mailbox. Easy and safe. Only once did I enter a house to get three big shopping bags of Legos but it was someone I had bought from previously.
I'm starting to sell a few of my own items, and have even just given away a few that I couldn't figure out how to price (like a bunch of outlet covers for child proofing - I didn't need them anymore but I figured someone would).
Some people will haggle but most will only respond if the price is right.
Tomorrow I have 3 people coming to pick up things. I plan to keep the money in a separate envelope and use it towards maybe starting my Lia Sophia business in the fall. Yes it all comes back to Lia Sophia ;)
But seriously, if you're looking to offload some stuff or are a garage sale fan but hate spending time driving around and finding nothing, give a virtual site a try.