Linux single-board computers, from the Raspberry Pi to the Pine A64.
I backed the PINE A64 on Kickstarter in January 2016, a project that raised US$1,731,466 from 36,781 backers. I chose the US$29 reward, paying about US$41 with shipping for the PINE A64+ with 2GB RAM, a cheap single-board computer.
In my earlier Raspberry Pi post, I noted I couldn't find any cases on Element 14, but they now stock them. I bought my Raspberry Pi Clear Case from Michael Cheng, who'd ordered a spare from Element 14, paying S$16.
The Raspberry Pi is a no-frills mini computer costing US$25 or US$35. Credit-card sized, it plugs into your TV and keyboard, and handles much of what a desktop does, from spreadsheets and word processing to games, and plays HD video.