In a similar vein, cheap usb microscopes, though less versatile are incredibly useful for soldering/inspecting PCBs

While I did like getting one, I have to say that in retrospect, I would have liked an auto-focus function, which low-end ones didn’t have when I bought one and I assume still don’t have. Unless whatever you’re looking at has a very fixed height, it’s kind of a pain to keep fiddling with the microscope to bring things into focus as you move an object around.