"When The Mechanical Design Process was first introduced in 1992, I insisted that it be priced at less than $50. I felt this was a fair price for a university text on the topic. McGraw-Hill, the publisher, agreed and released it at $49. Over the years, McGraw-Hill steadily raised the price over my protests."
January 1, 1970
https://en.wikiquote.org/wiki/David_Ullman_(author)