Small Computers:

<a href=http://tech.microbit.org/>Microbit</a>;
<a href=https://bbs.nextthing.co/>Next Thing</a>;
<a href=https://raspberrypi.org>Raspberry ∏</a>
<hr>Other lists: <a href=http://www.laptopmag.com/articles/the-8-cheapest-computers-in-the-world>Lap Top Mag</a>