Is 50 gold even actually an average price being paid? I would expect it to vary a lot between islands and even from realm to realm.
I have never paid that much for a unique item and with my one character I thought I was being very generous when paying 25 gold for one item, mostly because I wanted to make sure the advy kept selling me items. (I've purchased 5 items from the same advy.) The rest of the time I've paid closer to 5-20 gold depending on the quality of what is being offered.