Fair price for a Rodagon APO 80mm/f4

I have a Rodenstock Rodagon APO 80mm/f4 which I am not using and consider to let go. The barrel and internal lenses are in perfect condition, but the front lens has a small mark (approx 0.8mm diam) off-center and quite far out the margin of the lens. It seems like the mark is just in the coating. The rear lens have close to invisible mark due to a too rough cleaning procedure.

Can anyone give me a hint on how much I can ask for this item? Is it just garbage?

I'd say that in good condition, these lenses go for around $150-200 these days, but check completed auctions on eBay, because I haven't shopped for enlarging lenses in a while. In the condition you describe I suspect it would be on the lower end of that scale.