I saw an Action Comics #1 on display in New Haven, CT around 1974. I do not remember if it was $3,000 or $30,000. I was very happy to get a $1 double sized reprint for $1 a couple of years later. There was a Pep Morgan (Boxer like Joe Palooka) story in there that would be considered racist by some.
That double sized reprint was probably worth something.