My first eBay search produced a sum of $419! You can search completed listings to see if the same model has a good clearance rate - you can see what someone has asked and whether it has sold or not. It will also be clear what sort of money the sold ones are going for.

I'm with Steve, mine was free and frozen. I think if it's working well and serviced, you could probably ask anything you like ... the 'catch' is to attract the right buyer. Good luck!