Be careful, sounds a little suspicious
http://boston.craigslist.org/gbs/boa/4725495405.html
The deposit is a good idea on his part. When I have listed things for free on CL I have wasted A LOT of time answering phone calls and pointless/irrelevant questions and make appointments only to have people no-show. When you give something away, you certainly do not want your time wasted.
I gave away a monohull one time on CL, will never do that again. I must have gotten 100 phone calls (one at 2 a.m. A couple days later)and emails in a 3 hour time frame. Had people asking me to hold it for a month, help arrange shipping up the coast, find a marina they could store it at, etc... I don't blame the person for the deposit. He should have charged $100 just to chase off the people who will waste his time
The item on the ad is now gone. I usually put a low price on CL for things I want to throw out. It usually sells within hours after posting. In one instance the guy was here in 30 minutes to pick up an old chainsaw for $10. Nothing for free. No deposits, first here with the money gets it. And calls only, no emails as callers = buyers, emailers= tirekickers and question askers.