Where are you planning on selling it? If I were to sell it locally on craigslist (I'm in the NYC metro area) I'd probably start by listing it high, maybe $275-$300, and work my way down. I don't think I'd sell it for less than $200-$225. This assumes it's been thoroughly cleaned, lubed and adjusted with fresh rubber and is in perfect working order.
It could possibly fetch more on ebay, but maybe not. Figure $250-$350 range.