In 1974, The Altair 8800 microcomputer kit went on sale in the U.S. as a do-it-yourself computer kit.
Sold by Micro Instrumentation and Telemetry Systems (MITS), the Altair used switches for input, indicator lights as a display and was powered by a 2MHz Intel 8080A microprocessor. It sold for $397 as a kit or $595 fully assembled.
Learn more at http://www.wired.com/science/discoveries/news/2008/12/dayintech_1219.