I've done a number of eBay and Craigslist transactions. Best to always bring a companion to watch your back, and meet in a safe and busy public area, never at night.
A little while ago, while trying to buy some computer equipment off Craigslist, the seller told me he lives in Richmond (SF Bay Area, Richmond is crime-infested). Told him forget about it, but the seller sighed and says no one wants to come to Richmond. So we met halfway at an Ikea store parking lot near Oakland. Turned out to be a nice latin guy, reselling stuff he bought at a thrift store (still had sales tags). He made some money and I got great bargains. I have a bought a lot of stuff cheap this way. Don't let robberies scare you, just take precautions. Like not getting into the seller's car!