Question for the Ethicist

I go into a used book store in a small town. I have not been in the town or book store before and may not ever be there again. But I might be.

The book store is not fancy. It has a large selection of comic books, and a very mediocre selection of normal hard back books.

The book store has one person working there. She and her husband have owned the store for 17 years. It is their retirement business. The community they live in is not what you would call an upscale community, but it is in an area where there are a large number of wealthy people with weekend homes.

The books are priced on the first inside page. Most are priced in the $3 to $5 range. If they had any expensively priced books, I did not see them. They certainly do not stock rare items.

I found a book that I decided to buy for $5. On my way out, I saw another book that had always interested me, but a European statesman that I respected. The book was about 40 years old; the author died about 35 years ago. I pulled the book out and looked at it more carefully, and discovered - to my absolute surprise - that it was signed by the author in 1966, when he was about 85 years old. There was no question but that the signature was genuine.

I knew the book was valuable. I looked for the price. And, this turned out to be the only book that I saw in the store that did not have a price on it.

I took the two books to the proprietor and told her that I wanted to buy them, but that the one did not have a price on it. I did not tell her about the signature, or my assumption of value. She said: "It doesn't happen often, but sometimes my husband misses pricing a book." She looked at the book (I would say "fairly carefully") to see if she could find a marked price. One of the pages she opened to was the page with the signature. She said: "How about $3?" I said fine, paid by $8 plus tax and left.

Is what I did ethical? Should I have actually called her attention to the signature, and told her that this was a very hard signature to find, etc.?

I got home, and looked the book up on the internet (www.abebooks.com) to see if there were any signed copies available. There was one for sale, for $2900.00.

Does this very high price change anything in the answer to the question as to whether or not I did the right thing?

Should I do something different now?