Yugster offers the factory-refurbished Nokia DT-900 Wireless Qi Charging Plate in Black or White for $14.97. Coupon code "FreeYugBuck" cuts it to $13.97. With free shipping, that's $4 under the cost of a new unit and the lowest total price we've seen. It's compatible with the Nokia Lumia 920 and Lumia 820 and features a charging status indicator light. A 90-day Nokia warranty applies.
Of note: The countdown timer on the product page does not reflect an actual expiration time and resets daily.