A Prime transfer authority was a form of Romulan currency. This was a plastic rectangle used to represent huge amounts of money. Maiek tr'Annhwi offered one for Leonard McCoy's life that could easily have bought the good half of i'Ramnau. (TOS novel: The Romulan Way)

Types of currency
materials	acta crystal • gold • latinum • ludugial gold • silver
units	bilbok • cent • credit • darsek • dejebbit • dirak • dollar • drokna • ducat • galorine credit slip • ilec • kern • klon peag • laertian dinar • lek • lita • notch-rock • prime transfer authority • quatloo • sakto • sous • szeket • t'chak • talon • tri-esta