I'd say that right now it is a good time to find one, they are getting pretty cheap. I am guessing that the celeste colour was pretty popular in the '90s and even early 2000s but now I think people want something less flashy. This one I was watching was a steal for a Reparto Corse road frame and even this complete bike went for a cheap price.

Except for of course, the track frames which are overpriced, as CavMech said. The trend in track frames has priced some very mediocre stuff like Schwinn Madisons, or anything Italian, into the 400$USD range. If that frame is a celeste coloured Bianchi pista, even if it is made out of Aelle tubing, it goes for a grip. I think that it will slow down one day as all trends do, I cannot wait