What I would suggest is checking out the 'Sales' section and seeing if that has been sold before. That could possibly give you a good starting point
Best thing to do is post it up in the sales section and put down information that would be useful for those looking at it (i.e. length of time you've had it, how often its been used, if there was any big issues with it since you bought it etc)
Put on there that you are willing to accept suitable offers and see what comes back from the public around here.
Hope that helps