Last year we spent two weeks in a camping resort in Croatia and bought 1 liter of olive oil (bottled) in the resort's supermarket for ~220 kn (~ €29.50 at today's rate).
We realized that the price we paid for this (cheapest) oil was nearly 10 times more than what we would have paid in Germany for the same item. In contrast, other things like wine, milk products etc. were only a little more expensive than elsewhere but relatively normal, and as what you would expect to pay in a resort's market.
We didn't check whether the same high prices occurred in other markets in Croatia, but I think we would have observed the same thing.
Why was that so? In Greece e.g., or other places that produce olive oil we did not observe such high prices.