It’s not cheap but I have a small glass of grapefruit juice every day as it’s supposed to help lower high blood pressure. Finished one carton (Sainsburys) and picked up a new one (Tropicana) that I’ve just bought from Asda, which I thought felt a bit used already.
Checked the info on the carton and it’s 150ml light! Rather than supply it in a smaller carton to make it clear that you are getting less, (for 39p more) they just aren’t filling them to the top! So that’s Tropicana off my list too.