$624.
Ryzen 5 - 1400 / AM4 AB350M Micro ATX / 8 GB DDR4 RAM (2800mhz dual channel) / RX 480 (4GB) / 1TB HDD / Bluray Drive / 430 W PSU.
Just swap out the Intel CPU for the Ryzen 1400 ($169).
Bearing in mind that the RX580 will be out and on the market for several months by the time Scorpio is out, and the RX570.