As of 5 or so years ago, the lidar used for this on the research side of things started at US$10k per unit (and for "surveying" you can do ok with one-on-top but for navigating you need something smaller and not sticking out of the roof, so then the car itself is a blind spot so you want 2x or 4x units.)

As a robot developer, I was really hoping that high-volume self-driving would lead to lidar mass production (and thus price drops), and there was one promising non-mechanical lidar that was aiming for $1000/unit for an self-driving-grade sensor, but I've lost track of it...