This prices are from top user trading sites in greece/europe in august 2017.
Feel free to post prices from your country and compare with this.
As u will see lots of nvidias , in fact more nvidia cards are selling than amd and amd cards 470-480-570-580 are usually more than 300-320euros second hand.
i didnt bother much with prices of new ones because they are very expensive. 200-250 for a 1050ti for example.