The currency in Serbia is ‘Dinar’ - this is hard to come by in the UK as most banks don’t stock the currency.
You can buy your currency at Belgrade or Nis airport when you arrive.
Dinar banknotes are available in units of 5, 10, 20, 50, 100, 500, 1000 and 5000 coins are called ‘para’. Please, do not rely on credit cards for local purchases. MasterCard and Visa are not generally accepted. Cash machines are available in Belgrade town and Kopaonik mountain.
Exchange offices and banks abound, particularly in the centre and around tourist areas (Belgrade or Nis Airport - arrival hall, Main Railway station - exit area, etc.). They don’t charge handling fee for these services. In order to exchange money you are supposed to present your passport (usually in banks only). Always ask for a receipt and always count the money you received. All licensed exchange offices are properly signed (‘Menjacnica | Exchange’). Do not change money on the street! There is no foreign currency black market anymore.