Adorama via eBay offers the GoPro HD Hero4 Black Edition 4K Action Camcorder, model no. CHDHX-401, for $399.99 with free shipping. That's the lowest total price we could find now by $100, although it was $25 less three weeks ago. It features 4K video recording, up to 12-megapixel photos at 30 fps, waterproof housing (up to 131 feet), WiFi, and Bluetooth.