Cheapest Lidar I know of with reasonable quality is a Neato vacuum cleaner. Go to Target, get a vacuum, give it a lidar-ectomy, throw away the sucky parts, and you still have the cheapest LIDAR in town. 350 pionts, 5HZ scan rate. Indoor range about 5m, outdoor 2+m with a sun shade, accuracy at 5m about +/- 2cm. Great for hobby robots. Totally not sufficient to drive a car at highway speeds.