The BBC Micro At School
One computer, thirty children, and a turn each on Fridays.
Acorn's machine for the BBC Computer Literacy Project, which ended up in nearly every school in Britain.
It was built like a tank and cost the earth, which is why schools got them and homes mostly did not. Granny's Garden and Podd were the software everyone remembers.
The BBC Micro team later designed the ARM processor, which is now in almost every phone on Earth. That is not a small footnote.
Cost back then
£335 for Model B
Goes for now
£100–£400 working