Greek money was the Drachma. 13,5 US Dollars, 20 canadian Dollars, 9 pounds sterling made about 5000 Drachmas. Now, the greek money is the european money : the euro (€).
You can use Eurocard Mastercard, Visa, and traveller cheques. To lent a room, cash will be prefered. In the touristic places, there are many cash points and change offices.
In general, you'd better change your money in Greece. You only need some Europan money for your arrival. For example, if you take a taxi at the airport of Iraklio (Crete) to go to the bus stations for the main towns, and then if you go by bus to Agios Nikolaos (east) or Retimno (west), where you rent a room for one night, it coasts, for two persons, about 30 € (but ou have not eat).

Some prices in the Egean islands and in Crete (as an indication and from memory):
- accommodations: From 12 € for a room to lent in spring to 70 € in a luxury hotel in summer (for two persons). In general, for two persons, you can find a room in summer for 16 €. See the section Accommodations
- a complete dinner in a taverna where the Greek people go: about 12 € per person, or less (or much more if you eat fish); a Greek salad can costed 1,5 to 3 € : it depends on which taverna you go to ! Price of souvlakis (meat kebabs) can be between 2 and 4 €. See the section Food
- one cheese pie (tiropita): 0,3-0,45 € in the bakeries frequented by the Greek people. You can count double price in touristic shops. See the section Food
- taxi between the airport of Iraklio (Crete) and the centre of Iraklio: about 5 € ; about the same price between the airport of Santorini and Thira. See the section Domestic transports
- bus: between the main towns of Crete, distances are about the same (70-80 Km). Prices too, about 4,5 € per person. In Santorini, Prices are between 1,2 and 2,4 € (it is a small island). See the section Domestic transports
- boats between islands: it depends on which kind of boat you take (ferry or jetfoil), distance and the kind of seat you choose on the boat (floating bridge or cabin). Between Santorini and Iraklio (Crete), it coast about 7,6 € per person on the floating bridge of a ferry. Globaly, boat is a cheap transport between islands. See the section Domestic transports