Amazon with Dreame Smart Pool & Garden has the DREAME Z1 Pro Cordless Wall-Climbing Robotic Pool Cleaner on sale for $499 - 20% off automatically at checkout = $399 with free shipping.

• Works with 2.4GHz Wi-Fi or dual-band Wi-Fi (2.4GHz and 5GHz) networks.
• 8,000 GPH suction, 9600mAh battery (up to 180 minutes), covers 2160 sq ft in one charge