Good question. There are several 3D scanners in that price range, but I'm curious as to the difference between photogrammetry with a phone, something like the $800 SOL 3D, and the $10k+ handheld options.

The ~$1k 3D scanners out there advertise an accuracy of something like "up to 0.1mm," which puts them in the ballpark of the resolution a basic Prusa's likely to be able to reproduce, but I'm really unclear on how true that is in practice.

There's likely some actual Nyquist-Shannon ish corollary that will tell you how much higher your scanning res has to be than your printing res, but 2x is probably a safe bet. Not to mention "accuracy" tells an imprecise story. Does it mean that the best case scenario every point is at most 0.1mm from where it should be? That doesn't mean the same thing as "accurately resolves features larger than 0.1mm³".

No because 3D scanning is really, really hard. Much much more complex than 3d printing. There's no fool-proof way of determining the position and normal of a surface point other than to touch it. All EM based techniques must contend with the wide gamut of different interactions common materials will have with a given wavelength. Not to mention occlusion.

Any iPhone with FaceID is actually a very capable as a 3D scanner. I recommend heges, it has support for Lidar scanning as well (if you have an iPhone 12 Pro or a new iPad Pro).

https://hege.sh/