Remember that I'm not talking about the height of the season. And I'm not talking about Corfu, etc.
Went to Santorini first. Flew from Athens. Athens shocked me a bit. Prices were comparable with basically any west European capital. Santorini was kind of pricey, but I expected it. Didn't much like it. It's a weird place. And I've never liked beaches made of volcanic rock (which is all you get there). You've got couples from Korea on the esplanade who've flown out there for a weekend just to get married. That kind of thing.
Had a fantastic hotel room in a boutique hotel, though, with a balcony immediately facing the caldera. As I remember it, it wasn't through the roof. Maybe 100€ a night, maybe a bit more?
Caught the ferry from there to Naxos. Prices dropped hugely, for everything. I mean, like, 50€ a night. Hotel room, meals. Naxos was just about the right size to imagine living there, and I made vague enquiries about long-term rents/buying. Hiked up Mount Zeus (the home of Zeus, so legend has it!). Fairly rugged path, but not too high.
Paros, opposite, is even cheaper, so I'm told. Went from there to Iraklia (I think). And from there to Koufonisia. Everybody really nice, really friendly, and prices were very affordable everywhere. In short, I did a bit of a tour of the Lesser Kyklades. So with the exception of Santorini, I didn't head for the place that the hordes of kids go to to party. And I was there in April, May.
Later that summer I went to Iceland. Hiking holiday. That's a whole different story. Perhaps the most astonishing landscapes I've seen anywhere on earth, apart from the Sahara.
Oh, and prices through the roof.