Craig's list is free, but, IMO, it's a mistake to think of it as a free Ebay. I love Craig's list and Ebay and think they are useful for completely different things.
Craig's list is basically the garage sale of online selling. People are looking for a bargain. I do not know any people that have luck selling high end items (for more than giveaway prices) or selling things for profit.
Because it is free, there is no protection for either buyer or seller. Personally, I'd only sell (or buy) in person and for cash. WHen selling, I get about a 50% no show rate. Personally, I don't sell out from under someone. (If someone makes an appointment with me to buy something, I won't schedule another appointment before it. If someone calls about an item that I have an appointment scheduled for, I will schedule them afterwards and let them know that I will call them if the item is gone.) However, because of the high no show rate, many sellers will sell an item to the first person who shows up with cash.
Here are some things my mom and I have had good luck selling on Craig's list. If you use Ebay a lot, you'll be able to see the difference. My mom is currantly using it to get rid of many items of my late father as she is preparing to move:
100 mounted stuffed fish for $10 each
Fishing equipment (for about 10% new value)
10 year old, 60 inch, 400 lb television $150 (would have cost more to move than value or even to haul away for junk)
Ikea pressboard office furniture. $10-$25 / peice (great for student furnishing place. Again, would cost more to move than to replace)
Books. (free to .25, great to have out for impulse purchase if having a big Craig's list day)
Most other things I sell on Ebay. For example, gift cards, small electronic items, etc.
Hope this is helpful