Somewhere around 20 years ago, I purchased a page of original art of Action Comics no. 405. It is the October 1971 issue.
The page was pencilled by Curt Swan and inked by Murphy Anderson (with backgrounds inked by Jack Abel). At the time I bought mine, original comic book art was not too expensive. Mine was $100. I have forgotten who the dealer was that I bought it from.
The page was signed by Swan.
Today, Swan's original artwork, highly sought after, sells in the thousands of dollars. Key issue art commands more as do covers and splash pages. No, I don't plan on selling my page.
Here is the cover of the issue (by Neal Adams and Dick Giordano):