You haven't really give us any meaningful stats to be able to provide you with even a rough value. It could be a crap domain name with poor content, in which case it's probably not worth anything more then the domain fee. If the domains got some good content, then maybe upwards of $500, but it depends on the content, traffic and many other variables. PM me the domain name if you want and i'll take a look.
"Many of life's failures are people who did not realize how close they were to success when they gave up"