I have both bought and sold one over ebay. A Naildriver for a Specialty Archery - didn't get the good end of that deal.
There isn't a lot of point in bidding much before the last half hour.
Also look at the CBE site:
http://www.custombowequipment.com/
Their second cheapest is a really good sight, and isn't all that expensive.
You can happily shoot those things without the scope, and frankly It isn't the scope that takes getting used to for me, it is all the fiddling. Once I found either the right clarifier peep, or the right aperature, I pretty much forgot about the scope. Up until about 5 years ago, it wasn't all that uncomon to see guys just shooting the pins with the level in them and no scope. I did that again last year, and found it worked great, and my eyesight isn't all that strong any more. I just mention it because it is one way to ease into using the moveable sights.
I have had good luck with the Specialty archery scopes, of all kinds. If I was in the market for a new one, it would probably be the Shrewd, though I haven't seen it. Theirs just looks really solid, being all milled AL. I have also heard good things about the FEATHERVISIONS lenses they use (as do other scopes).
http://www.shrewd-one.com/scopes.html