I take it this is a 12ga rather than say the 28 ga? If so, in view of their discontinuance and the long documented problems with top lever spring breakage, firing pin breakage and, in some cases, poor barrel regulation (although I believe that was only in the first 2 - 3 years of production), about $650 - $750 would be fair market value. Their discontinuance will drive prices lower, ie into this range, for the next year or so. For whatever reason, the RRL in 28 ga has had remarkably few issues and either through less stress of parts or better initial quality, they have held up better. The 12 ga, I would put about on par with the CZ Huglus, albeit lighter and somewhat better finished.
If you can get it cheap, it may be worth the gamble. They're pretty good looking guns but sadly they have developed a bad reputation based on extensive faults.