The ODROID-C2 is a 64-bit quad-core Single Board Computer (SBC) that is one of the most cost-effective 64-bit development boards available in the ARM world. It will be available for purchase on March 2, 2016 at US$40. The mass production will be started from February 15, 2016 and the first shipping date is March 4.
A further step forward from the already good ODROID C1. If the 64-bit implementation is not troublesome, we'd like to port RuneAudio to it in the future.