It’s impossible to buy anything but the most entry level Radeon graphics cards right now.
That’s expected at the high-end, as AMD’s enthusiast-focused Radeon RX Vega graphics cards won’t launch until the very end of July. But even “sweet spot” mainstream graphics cards like the superb Radeon RX 570 and RX 580 can’t be found right now, with all models either out of stock or selling for wildly inflated prices online. You’ll find a couple of PowerColor RX 580s ostensibly selling at standard cost on Amazon, but if you look closely you’ll see the models are out of stock. Amazon’s selling first dibs on inevitable restocks. You probably shouldn’t expect to see the cards in your hands any time soon.