The Commodore 64 is the single most popular computer system ever sold. Released in 1982, the Commodore 64 had a 1MHz CPU and two big draws: a powerful, programmable sound chip and powerful graphics for a 1982 computer. Even better, the Commodore 64 cost a reasonable $595 and had 64KB of RAM (hence the name). And the Commodore 64 could be plugged into a TV, making it a hybrid computer/video game console.
When it was released in 1982, the Commodore 64's graphical capabilities beat the pants off other popular computers like the Apple II. Thanks to its price, the Commodore 64 sold well. And it kept selling. As the computer became cheaper to produce, Commodore cut the price, keeping it popular throughout the 1980s. It continued to be produced until 1994.
Affordable modems made the Commodore 64 a great computer to get online with, and like most systems of the day it used the BASIC programming language. It was a popular software platform. By the end of its life, the Commodore 64 had sold more units than any computer before or since. Estimates vary from as few as 12 million to as many as 30 million. The Commodore 64 likely sold an incredible 17 million by the end of its life [source: Old Computers].