I've found ebay is a great place to sell smaller, cheaper things that I probably couldn't find a buyer for on craigslist. Stuff of lower value (<$50) that I wouldn't mind losing anyway really, like an extra laptop battery or an old cell phone. For those things, it's not worth the effort to find a craigslist buyer and meet up somewhere, but tossing it into a flat rate box is very easy.

As things get more expensive on eBay, you become a bigger target for scammers and stand to lose much more, so it becomes a terrible option both because of how many scammers there are and their policy of screwing over sellers. Also the more expensive it is the more likely I'll be able to move it on craigslist which is a sure thing.