Signed Baseballs Auctioned in 1921
 

I found this article related to a benefit game for Christy Mathewson, who was dealing with TB. The game was played on September 30, 1921, and around $50,000 was raised. Two baseballs were auctioned at the event and the article (attached, sorry for any lost detail) says:

"A baseball, autographed by President Harding, Vice-President Coolidge, Babe Ruth, Matthewson [sic] and George Kelly, was auctioned off for $750. Another ball, autographed by Hans Wagner, sold for $250."

I wonder where those baseballs are now, and how much they'd go for in an auction today...

The inflation conversion from 1920 dollars to today would be about 9,385 aprox, but of course, in an auction a ball like this would go higher (depending on condition). Anyway, that was a lot of money back then.

I would think those prices were for the charity. I can't see them reflecting era value.

Follow Up
 

Here's another newspaper clipping, with more detail about what was sold and who the purchasers were. Truly Warner was a hat retailer.

100 Matty-signed balls for $5.00 each; now that's a deal...

I love seeing clippings like those because it proves that there are potential examples of some of these players on baseballs etc.