The value of a "Yankee dime" depends on how much it is valued by the recipient from the giver. A Yankee dime is not a coin, but rural, southern slang for a quick kiss.
The reference below is found within the pages of Harriet Clara Morse's 1908 book "A Cowboy Cavalier."
“I’ll bet Miss Marian a Yankee dime it won’t rain for a week,” called out Tadpole.
Still popular in the South, the term is derived from the Civil War era and cited as far back as 1846. Another similar noun is a "Quaker nickel," which refers to a small token of appreciation.