A dime was a unit of currency on Earth used in the United States of America and Canada. It was equal to one-tenth of a dollar ($0.10), or ten cents (10¢).
In 1893, a beggar asked Data for whiskey, and when Data responded that he had none, the beggar told him that he would take a dime instead. (TNG: "Time's Arrow")
When Worf requested that the 1960s hologram Vic Fontaine play the same song over and over again, Vic used an old expression: "It's your dime." This referred to the fact that Earth jukeboxes, which played songs on demand, once accepted dimes to play a song. (DS9: "Image in the Sand")