You have to be really diligent to get hold of an RX 500 or 400 series card right now! They come online and are scooped up within minutes.

Funnily, I was an early buyer of the R9 290. Though I knew what Bitcoin was, I only learned of mining when I read about the R9 290/X shortages. In hindsight, I should have given it a shot - people were mining multiple BTCs back then on their 290s! I remember the price was around $150, and even at that price it was profitable. Months after the R9 290 released, the price was already $1,000, and then Mt Gox happened. My sympathies!