Amazon offers the Pyle Car Accessory Kit, model no. PLCM7200, for $53.39 with free shipping. That's a buck under our mention from three weeks ago and the lowest total price we've seen. (It's a current low by $7, outside of 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 $54.45 with free shipping.