I love using Craigslist to buy stuff... just make sure to meet in a public place and NEVER allow someone to "pay" with paypal (they can make it look like they did even though they didn't)
Seriously! $19 bucks a month to start a group and all you get is headache after headache! Once KiwiConnect.com comes out in my area I'm going to that! (free AND none of the privacy issues of Meetup such as people seeing where you are without even having a Meetup account)