I once bought my pride and joy, a log-log slide rule with a magnifying cursor. I thought it was the most wonderful thing ever, all those scales etched in beautiful pure white plastic, only clean with dilute cold detergent, with a magnifying cursor so you might get four significant places if strain a bit.
a friend wanted it, he begged and offered 20 shillings, and he tricked me by lying what 20 shillings were.
I had no slide rule but I did have 20 shillings to go and buy another one.
The shop did not have one and they never heard of it, they had some 6" ones and some 12" ones but none was log log and nobody had heard of a magnifying curser.
So I went to this fellow and said can I have my slide rule back, he said "no" "I have you 20 shillings for it and it was a deal, so I said 20 shillings was no good because I cant get another one, you are a thief!
Poor bloke, he went out one day and I never saw him since.
That is why capitalism is the evillest thing there is.