Facebook has been where I've had the most success. There are two active 'yard sale' groups for my area and I've sold quite a bit there with no fees. Because they're local the buyer comes to you - I prefer not to meet at my house for security reasons but generally meet at the corner store - so there are no shipping fees, there's no listing or final value fees, and the audience is narrower than Craigslist which seems to make for fewer weirdos and no-shows.