What's an average price? There are only so many originals available. At some point the available just drys up.
I think that I remember at one point seeing a few at $2,500 available and then the repro appeared for $1,100 and the asking prices began to drop.
So what are they worth? Whatever you can get for them when you go to sell it I suppose?
For me it always seems that it is going to cost me double to get back what I sold my original for.