The Raspberry Pi makes a great USB webcam for $100
There are many Raspberry Pi projects where I spend a few hours (or dozens of hours) building something with a Pi, and realize at the end that not only could I have purchased an off-the-shelf product to do the same thing for half the component cost, but it would work better too.
But this is not one of those projects:
The Raspberry Pi and its HQ camera make a surprisingly potent webcam, and if you want to cover the basics, and rival the image quality of all but the highest-end dedicated webcams, you can do it for under $100.
Above is a single frame from a recording I did with the HQ Camera on my Raspberry Pi Zero W connected as a standard USB webcam using the Camera app on Windows 10 on my Dell laptop.