In the Mad Hatter's tea party, featured in "Alice in Wonderland," what was the price marked on the hat?

The mad tea party is one of the most familiar highlights in Lewis Carroll's 1865 book “Alice's Adventures in Wonderland.” The tea party is hosted by a character known as the Hatter, along with the March Hare and the Dormouse. The Hatter is usually referred to as the Mad Hatter, though this term was never used by Lewis Carroll: however, the Hatter and the March Hare are referred to as "both mad" by the Cheshire Cat in an earlier conversation with Alice.

The Mad Hatter's signature top hat is not referred to in the text of the book: it comes from John Tenniel's illustrations for the first edition, in which the character wears a large top hat with a hatband reading "In this style 10/6." This is further elaborated on in "The Nursery 'Alice'," a shortened version of "Alice's Adventures in Wonderland," adapted by the author himself for young children. Here it is stated that the character is wearing a hat on his head with a price tag containing the numbers 10 and 6, giving the price in pre-decimal British money as ten shillings and sixpence (or half a guinea). The “10/6” label on the hat appears also in more recent cartoon versions of the “Alice” story.

One guinea back in 1865 would have been equivalent in purchasing power to about £161 sterling in 2023. So, the cost of the hat in terms of today’s currency would be about £80.50.