Greece offers good value compared to Western Europe. Budget travelers can manage €50-70/day on the mainland: guesthouses run €25-40, a gyros or souvlaki costs €2-3, and bus travel between cities is cheap. Athens museum entry is €10-20, with free entry on Sundays outside peak season.
The islands cost more, especially Santorini and Mykonos — expect to pay double Athens prices for accommodation in peak season (July–August). Ferry travel between islands ranges from €15-50 depending on distance and speed. Crete and the Dodecanese islands offer better value.