A $5 PI? FeaturesBroadcom BCM2835 ARMv6 system-on-a-chip, running at up to 1GHz512MB on-board RAMUnpopulated 40pin GPIO for added flexibilityMicroSD port for OS and storageMicro USB power input1x Micro USB Data port and Mini HDMI Port(comes with Micro USB ‘On the Go’ adapter and Mini HDMI to HDMI adapter) http://www.element14.com/community/docs/DOC-79263?ICID=rpimain-topban-link
Imagine the farm that could be built with 1 BTC!
Hmmm... not quite $5 though.
Would require an additional pigeon farm for communications - apparently networking is not included