In any market that you look into there is always an up and down slope of pricing and stock due to supply and demand, having enough product and other means.
Right now all of the RX series graphics cards from AMD are either priced at over $400 or they’re completely out of stock on other websites.
How Come?
The answer is BitCoin mining. It’s unfortunate that the market had to move so drastically because of it but that’s definitely why we’re not seeing any RX 480’s/RX 580’s on the market for an acceptable price point right now.