When I used to work in a supermarket, I hated the stupid customers. This is a classic example. One of the soft drink companies fairly regularly gave away 50% free.
Therefore, for the same price, the bottle would be 3 litres in size rather than 2.
The amount of people who didn’t like that.
“Excuse me, where’s the 2 litre bottle?” “Oh, it’s the same price miss, you get an extra litre for free.” “But I don’t want 3 litres, I only want two!” Sigh!
Just a simple kitchen timer.