There are two currencies used throughout Cuba: the Cuban Peso and the Cuban Convertible Peso. It is the latter that is most commonly used by tourists, though. There are numerous ATM machines and foreign exchanges bureaus throughout Varadero where you can get your currency when you are out there. Cuban currency isn’t traded internationally, so you can only exchange it over there. It is best to take sterling or Euros with you to do this. Or you could always look into getting the Thomas Cook Cash Passport.