Orange Pi Lite
The Orange Pi Lite is a cheap and cheerful Chinese single-board ARM computer. It has a 1.2GHz quad-core AllWinner H3 ARM7 SoC and 512MB of RAM.
I actually prefer this to the Raspberry Pi boards, since the hardware is better and the people behind it are actively trying to get all their patches into the mainline Linux kernel.
Also, the best part about this is the price — $12 (+$4 shipping)! You can also get a set with a power supply, enclosure, and 8GB SD-card for $24.40 (+$6 shipping)! Just attach an HDMI monitor or TV and it would make a great little machine for a non-demanding user (e.g. browsing the internet, watching movies, etc.). I think this is great!
However, the processor can get quite hot (especially if you put the board in an enclosure), so adding a small heatsink to it is a good idea.
- Miscellaneous information about the Orange Pi Lite on linux-sunxi.org
- Wifi drivers for the Orange Pi Lite's RTL8189FTV SDIO chip
- Status of various board features in the mainline Linux kernel (look at the H3 column for the Orange Pi Lite)