Craigslist is a prime place to find gear, but it's kind of hit or miss with rare stuff. For common stuff like Rebel DSLRs or popular point and shoots, you will find plenty of listings.
I've ordered from KEH before. I wanted a carbon fiber tripod, they sent me an aluminum version. They let me keep the wrong item for a week, to make up for the delay in receiving the right one. An honest company, they are unlikely to screw you on an item description.