This paper that I wrote describes how to build a 3D scanner out of parts for less than 60 Euro and parts that were extracted from old printers, notebooks and so forth.
The scanner will be good for scanning a 360° field around its own position at distances of approx. 0.3 to 5 m. So basically this scanner is optimized to scan rooms and objects of a few centimeters up to a couple of meters size. It creates a point cloud that resembles the visible surface of the scanned area as viewed from the position of the scanner.
point cloud of a chair and a mug scanned with the 3D-scanner, the chair casting a ‘shadow’ on the wall behind it
a window board scanned from slightly below with the 3D-scanner
violin on a book scanned with the 3D-scanner