With activation of a 2-year contract, Amazon offers the recently-released HTC One M8 32GB Windows Phone 8.1 for Verizon in Gunmetal Grey for $49.99 with free shipping. That's the lowest total price we could find for this well-reviewed device by $50. It features a 5" 1920x1080 (1080p) touchscreen LCD, 2.3GHz quad-core CPU, 32GB storage, 5-megapixel front-facing camera, 802.11ac wireless, LED flash, Bluetooth 4.0, and Microsoft Windows Phone 8.1 OS. Deal ends March 31.
Update: Note that it's temporarily out of stock, but can still be ordered at this price for delivery when available.