a Yankee dime

[Teruhiko Fukaya]

I came across a sentence like the following in a novel: "He didn't give a Yankee dime about anyone
but himself."  From the context, it apparently means, "He didn't care about anyone but himself."
Since I couldn't find the expression in the dictionaries I have, I ran some search on the Internet
and found out that the expression "a Yankee dime" means "a quick kiss on the cheek" in the Southern
dialect, but nowhere could I find an explanation why it came to mean that.  Does anyone know the
etymology of this expression by any chance?  Also, how common is the expression in the South?  Thank
you in advance for your help.

Teru