I bought one off a user here from Brazil for $12 back in 2007, but I think it ended up being more than twice that amount with all of the shipping costs associated with getting something out of Brazil factored in!
I really don't know what the current price might be, but they are quite a bit tougher to come by now. I would personally think over $25 would be a reasonable thing to ask for - but I have not seen any recent sales.