For sale: gadget that was the making of a geek called Steve Jobs

It has no keyboard, no monitor and comes with just 8 kilobytes of memory – enough to hold about a 225th of a single song track – and is worth more than its weight in gold.

An Apple I, one of the world's earliest personal computers, will go up for auction later this month and is expected to fetch around £150,000.

Designed by Apple founders Steve Jobs and Steve Wozniak, the computer was built by hand in a garage owned by Mr Jobs's parents.

In 1976 and 1977 the pair of fledgling hardware designers handmade 200 of the machines, which helped kick-start a technological revolution that brought affordable computers out of science labs and into people's homes.

Unlike most hobby computers of the time, which had to be assembled from kits, the Apple I came partly assembled, making it the closest thing at the time to a computer that worked straight out of the box.

Only an estimated 30 to 50 units are still known to exist. But according to Christie's, which is holding the auction on 23 November, very few of the surviving Apple Is are in "such good, near-original condition with associated ephemera and full provenance".

For collectors of retro hardware, part of this particular computer's appeal will lie with some of the paraphernalia that accompanies the lot. It comes in an original box – with the return address pointing back to the California garage where Apple Corp began – and features the original Apple logo, which showed Isaac Newton getting hit on the head with an apple.

It also includes a signed note from Mr Jobs, the original manuals and an invoice dated 12/07/1976.

Most of the technical genius behind the Apple I came from Mr Wozniak, known amongst tech fans as the "Wonder Wizard of Woz". Mr Jobs brought magic to marketing and selling, something which has helped him turn Apple into a global company with a die-hard core of fans.

The pair met in the early 1970s as high school friends working on a mainframe computer, and decided to set up their own company. They sold Mr Wozniak's scientific calculator and Mr Jobs's Volkswagen van to raise money for their new enterprise. The Apple I was the result of seven years of work, trying to figure out how to make a comparatively cheap, mass-produced computer that could be easily assembled by hobbyists. It lacked a case, power supply, keyboard or display, which had to be provided by the user. But the fully-assembled circuit board, complete with more than 60 chips, was a revolutionary design. Previously customers had to solder their own motherboards, but the Apple I helped lay the foundations for the company's first mass-produced and highly successful home computer, the Apple II.

Not all tech reporters are convinced the computer will fetch such a high auction price. says: "Despite its incredible rarity, the Apple I has previously been known to fetch at best $50,000 at auction, and typically garners more like $14,000 to $16,000." Others quipped that the original price tag – equivalent to about £1,500 in today's money, was simply the start of Apple's tradition of selling its hardware with a higher price-tag than many of its competitors. "Even 34 years ago Apple's hardware was shockingly expensive," remarked Steven Mostyn, on Tech Herald.

Those unable to fork out such a large amount of money for a piece of computing history can rest assured there is a cheaper alternative. Last year an Apple fan unveiled the Replica I, a new copy of the Apple I built with Mr Wozniak's permission, which retails at $149.