The Apple II was the machine that can be considered to have kick-started the mass-market personal computer. It made its debut at the first ever West Coast Computer faire which opened on April 15, 1977.

In  April 1976 that Steve Jobs and Steve Wozniak founded Apple and started to sell their first computer. It was a single-board machine that was supplied without a case and only 200 were ever made. They originally sold for $666.66.

When number 82, which had retained its original packaging and a signed sales letter from Steve Jobs came up for sale last year at Christie's auction house it London it sold for $210,000 to Italian businessman and private collector Marco Boglione who intended to restore it to working order.

The design of the Apple I matured into the Apple II, which made its debut at the first ever West Coast Computer faire which opened on April 15, 1977. This was the model that ushered in the modern era of computing. No more were users content with text only monochrome displays - colour graphics was the thing - and computers became commodity items and occasionally design icons. More importantly they were no longer just for enthusiasts even if their owners often were very enthusiastic.

Further reading:

Steve Jobs and Apple

Steve Wozniak

Computer history under the hammer

Christies sells Apple I but not the Turing papers