I haven't seen many for sale in the UK. The limited number of transactions therefore makes it very difficult to identify a 'typical' value.
I bought a frame, (with Ouzo Pro fork and WR seatpost) never been built up, from a chap who had two other Pegs. I paid £700 when the list price (Marcelo) was around £1,500.
I have seen an ad in the UK in the past couple of weeks and the seller is asking close to the RRP. (He cites the lengthy waiting list and the barely used condition as reasonable arguments for the price level).
Have you narrowed down the size, yet?
Keep us informed of your progress,
David