Prices have been tumbling on my server - Aerie Peak EU - and I just picked one up for 4000g. How does this compare to other servers?
I was tempted to post this question today myself because I've observed the same over the last couple nights. A complete Nobles deck is ranging from 3500-4000g on my server this week; a ready-to-use trinket is 5500 or so.
EU Alonsus - advertised on trade @ 4,3k initially, then 4,2k, and then I left Dalaran... about 500g cheaper than my estimation of buing single cards, as there were not all of them on AH...
roughly 5k on my server, although, with darkmoon around this week prices are about 6.5-7k. it would only make sense that prices go up with the faire around and drop after it leaves. for the most part id say the average price hovers around 5k though.
On Dark Iron i have seen them go for as little as 3,500 recently. I'd say that they will probably keep dropping as more and more people pump out the northrend darkmoon cards.