Most foreign cuisine such as Japanese, Indian, Chinese (the most common), Mexican, and Thai, if you can find it, is over priced. The Greeks believe they are being served something exotic and are willing to pay extra for it. I am talking double or even triple what you'd pay for the same thing in the States. The 12$ Burrito for example. The $10 Pad Thai. Where is the wasabi and my buddy General Gau?
Unlike the USA, UK, France, Germany, Austria and other heavily industrialized countries, Greece isn't full of emigres from all over the world... from the Balkans and China Yes, but Japan, India, Thailand, Vietnam, Cambodia, and Mexico, NO! There are very few.
So, to give them their due (the Greeks), they haven't been as exposed to the "real thing" (or what, to us, passes as the "real thing") as lots of us. There are good Italian restaurants here, however, as lots of Italians have moved here and opened restaurants.
There is an abundance of inexpensive seasonal produce to be had in Greece. Its far less expensive than the USA where we often pay a dollar or more for 3 lemons. Here you'd pay 20 cents or less. Lettuce, cabbage, apples, pears, cantaloupe, watermelon, onions, carrots and just about everything you can think of and a few you can't are to be had here. Prices have risen 20% to 30% with the introduction of the Euro!
But some are grown with hormones and the way to tell is that they look too big. Also they should be thoroughly washed before ingestion and my mother even peels them. Hormones are not supposed to be legal in Greece but some of these fruit & vegetables looks as though Jack in the Bean Stalk grew them!
For a list of the rotating Athens Street Farmers Markets when and where go here.
One can always purchase, during business hours, meats and veggies at the Athens Central Market and numerous MANAVIES or vegetable shops sprinkled around Athens too.