Is $80 on Amazon not affordable? If they had grey ones available I would be on it in a heartbeat.
Looks like the Adidas D 773 II based on the silhouette of the shoes along with the traction pattern matching. At 1m 2s you can see the traction pattern of the shoes as number 15 goes to receive serve. If nothing else, I'm pretty sure they're a shoe made by Adidas.