Because it amuses me, here is a list of stuff. My impression, obviously.
Spinach (though kind of sweet)
Alcohol (particularly spirits, excluding whisky.)
Fruit (when mouldy - not joking, a mouldy peach was discounted to about $2)
Good + expensive:
Rice (!!!!!!!!!! Japanese short grain)
Wholemeal anything (though I did find some brown rice in a little backwater town.)
Goat cheese, haloumi
Dips (not made of cream cheese)
Also, chicken breast is pretty well the cheapest part of the chook, because it has the least fat.