The ZX81 was the first mass market home computer. Costing £69.95 built and £49.95 in kit form when first introduced. The machine came with only 1k of memory, black and white low resolution graphics a membrane keyboard and no sound. The software for the ZX81 was abundant and pushed the machine to it's limit. The machine also had built a large array of different addons such as printers, sound devices, keyboards, memory expansion etc.