Amazon offers the Pyle Car Accessory Kit, model no. PLCM7200, for $51.29 with free shipping. That's $2 under our expired mention from four days ago and the lowest total price we've seen. (It's a current low by $8, excluding the mention below.) It includes a nightvision-capable rear view camera and clips on to your rear view mirror. The mirror features multiple video inputs for additional devices.
A close price: Walmart charges $52.38 with free shipping.