>Cepton Technologies offers Nova [0], Nova-Ultra [1] sensors both at a sub-$100 price point

Where? How? I'm only seeing the Nova on ebay for between $4000 and $5000.

Cepton primarily operates B2B, as B2C demand for specialized LIDAR like this is pretty low. Anything you find on eBay is either a leftover dev kit or salvage. This is pretty much the case for MicroVision, Ouster etc.