Make your own computer - Raspberry Pi, here is a start https://www.raspberrypi.org/
There is an education section. The Pi exists in a world of single board computers.
https://www.element14.com/community/docs/DOC-88320/l/2017-year-in-review-single-board-computer-and-microcontroller-board-comparison-chart?CMP=e-email-e14NL-Dec17-SBC It is now on about its fifth revision. This other link provides a table summary of a number of different manufactures of the computers. The last table in the stack describes Pi.