hmm.. hard to tell... usually these don't really sell but you can give it a try - good luck! my advice: use a paid domain next time
ya of course.. the buyer could use the same co.cc domain or buy a new one and then do redirecting or something like that.. you could also mail the co.cc site owners for help. they may be able to help u
If your site content is good, why not give it a try although I believe it's not as easy if you have your own domain.
Give as much information as you can. Is it making any money? If it is, how much? How old is it? What's the traffic it's getting? etc You might want to open a topic in: http://forums.digitalpoint.com/forumdisplay.php?f=59 Good luck