Hyperspectral imaging refers to imaging in which a spectrum is acquired for each pixel in a captured image. A paper by Jairo Salazar-Vazquez and Andres Mendez-Vazquez details an easy to assemble hyperspectral device for just $500 which can take a spectrum from 400-1050 nm with a wavelength resolution of up to 2.1 nm and a pixel resolution of 116×110.
A detailed bill of materials and design files are available in the main text of the paper. It also includes a nice chart of a comparison to similar systems published in the past. The latter half of the paper details build and operation instructions.
Further files and a wiki-page can be found on the projects OSF page, which includes a detailed build videos and operating tutorials that are referenced in the paper.