Wilbur Wright to the Secretary, Smithsonian Institution - June 14, 1899
The History: "I have to thank you for your letter of June 2, in which you kindly enclosed a list of selected books treating on aerial navigation. I also wish to thank you for pamphlets #903, 938, 1134 and 1135 from the Smithsonian Reports. I enclose one dollar currency for which you may send me Experiments in Aerodynamics [by] Langley."
Wilbur paid one dollar for Samuel Langley's book, "Experiments in Aeronautics". That sounds very inexpensive, doesn't it? Prices change over time. You may know this from your own experience. Look at this issue of the West Side News. (Click on the newspapers to obtain larger images.) Look for prices and compare them to today's prices.