I've seen some go recently on other shards for around 5-10m, but I've known of people paying as much as 10-15 in the past as well although I believe the value has dropped somewhat in the past year or so as more have been brought out of old chests and put on the market. As far as the trade you made though, I'ld say you came out on top as PBD's generally aren't worth more than 20-50k(IME), unless it was one that belonged to you that was lost.