score:5
Residents of towns and small cities in Greece usually shop from:
Small grocery stores are usually used only for emergencies, fixed priced goods (prepaid cards and tobacco products mostly) and food to be consumed on the go (soft drinks, ice cream, etc.). They are far more expensive than supermarkets, but usually conveniently placed and open for more hours.
Now, compared to the Netherlands, in my experience, you will find very large price differences in some products even in large supermarkets in Athens. Some cheaper (vegetables, fruit), some more expensive (dairy products).