Hi-
I think I sold a typed Goudey letter, signed at the bottom, for about 150.00 a few years ago. There was no content related to cards, however. I would assume a letter with content like that would go for a lot more. Below is a link to a BST post selling a stock certificate about a year ago.
http://www.net54baseball.com/showthr...ghlight=goudey
I am sure someone else will have a better idea of the current market value.
If you like all things Goudey, check out the link below. It is related to the Net54 Nonsports forum, and contains a gallery of various nonsports Goudey items.
http://www1.coe.neu.edu/~dan/z-ns-start/all-goudey.html
Good luck with the hunt!
Alan