alt Hacker NewsAh thanks, didn't think about that.
I just checked and REWE only lets you sort by absolute price. But honestly, you can compare prices so much better on their website than in a physical supermarket already [0].
[0] https://www.rewe.de/shop/c/frisches-obst/?sorting=PRICE_DESC You have to enter a random zip code eg 20249
there is this "400g (1 kg = 3,48 €)" - would be pretty easy to sort results by that I'd guess, good idea!