They sell new for around $200. $150 is more than I'd pay, but it is not unreasonable if it is in good shape.
http://swfa.com/Redfield-Revenge-Rif...pes-C4180.aspx
I don't know a lot about the Revenge except that it is imported and not as good as the USA made Revolution. For my money I'd buy the Revolution in a 3-9X40 for around $200. You'd have a better scope for only a little more money.
http://swfa.com/Redfield-Revolution-...pes-C4179.aspx