Lidl isn’t too bad for it, at least not around here.

Sainsburys is probably the worst for it around here. A lot of the most popular items are routinely marked up 40%. The supermarket I work for, which shall remain green and nameless, is getting worse for it too.

Aldi is doing it right IMHO. Doesn’t have an app, doesn’t accept coupons, just tries to get people through the door as fast as possible and pass some of the savings on.