List of single and dual core single board computers

List of selected Single Board Computers

Here is a list of typical ARM based single board computers.
More boards and additional info can be found on Wikipedia.

After cheap quad core computers like Odroid C1 and Raspberry Pi 2 entered market, it makes only sense to use them for special purposes (e.g. lower energy usage).

ARMv6

Raspberry Pi Zero 

• Broadcom BCM2835 1GHz
• 1x ARM11
• 512MB RAM
• One micro USB Port
• One mini-HDMI Socket
• No Ethernet
• 5$

Available since End of November 2015.

Raspberry Pi A+

• Broadcom BCM2835
• 1x ARM11
• 256MB RAM
• One USB Port
• No Ethernet
• 20$

Low power consumption.

Raspberry Pi B+

• Broadcom BCM2835
• 1x ARM11
• 512MB RAM
• Four USB Ports
• Ethernet 10/100MB
• 25$

Rather slow CPU but excellent software support. For general purpose you should better use the newer Raspberry Pi 2 which sold for 35$.

ARMv7 Single Core

BeagleBone Black

• TI AM335x
• 1x A8
• 512MB
• 45$

A10-OLinuXino-LIME

• Allwinner A10
• 1x A8
• 512MB RAM
• 39$

C.H.I.P

• Allwinner R8
• 1x A8
• 512MB RAM 
• 4GB NAND Flash
• Wifi 820 b,g,n and Bluetooth 4.0

This was advertised in May 2015 on Kickstarter for only 9$ and a huge success. But you have to add 20$ shipping and 15$ for HDMI adapter and wait until  May 2016 (or January 2016 without adapter).

 ARMv7 Dual Core

Banana Pi

• Allwinner A20
• 2x A7
• 1GB RAM
• 40$

CubieBoard 2

• Allwinner A20
• 2x A7
• 1GB RAM
• 65$

A20-Olinuxino-Lime

• Allwinner A20
• 2x A7
• 512MB RAM
• 33EUR = 43$

A20-Olinuxino-Lime2

• Allwinner A20
• 2x A7
• 1GB RAM
• 45EUR = 58$

pcDuino3 Nano

• Allwinner A20
• 2x A7
• 1GB RAM
• 39$

These Boards are all Allwinner A20 based and have decent software support. If you like to support Open Source Hardware (you should!),
take an Olinuxino board. If you need the lowest price, Banana Pi or pcDuino might be the cheapest ones depending on shipping costs to your country.