Do you still have your Apple I computer from 1976? Less than 50 Apple Is are estimated to be in existence today, with only six known to be in working condition. Sotheby's auction house is putting on sale a rare working model of the Apple I, the first Apple computer with the original cassette interface, made by its iconic founder Steve Jobs and his partner Steve Wozniak. The offer will also include operating manuals and a rare BASIC Users' Manual.

The device will be included in the Books and Manuscripts sale on June 15, 2012. What is the expected going price? Sotheby's is estimating it will go for between $120,000 - $180,000. The sale will also include a report written by Steve Jobs in 1974 while he was working at a gaming company Atari. It is estimated to fetch between $10,000 to $15,000.

The Apple I kick started the personal computing revolution as users could type letters on a keyboard rather than working through a panel of lights and switches.

The Homebrew Computer Club in Palo Alto was the first to receive the creation of Steve Jobs and Steve Wozniak. Despite being the most complete device of its type available at the time, the Apple I did not come with the monitor, keyboard, power supply, or case that constitute the modern computer.

The computer did not receive a good response and was dismissed by everyone except Paul Terrell, the owner of a chain of stores called Byte Shop. He ordered 50 units for $500 each, which he then offered to the public for $666.66 apiece.

Terrell insisted that the circuit boards come fully assembled rather than as kits. Jobs and Wozniak built the 50 in just 30 days. An additional 150 units were developed by Jobs and Wozniak, which they sold to friends and other vendors for the retail price.

The auction ended with two people bidding in a war that saw the Apple I computer being sold for $374,500.