Got to have a price, them's the rules.
If you have no idea what it's worth (or what you'd realistically sell it for) then post in the Appraisals section.
(And a pic of the RIF, with your username and the date written on a bit of paper next to it, would help people feel a bit more confident you're not one of them 'orrible oiks running a scam - seeing as you've got zero feedback at the moment)