Firstly a highly over rated Australian cereal:
Weet-bix.
I think families buy it because it's cheap as fuck and supposedly healthy due to the fact that it's really just dry pressed bits of wheat pressed into brick shapes. Lots of people seem to like it, can't see why myself. When it's fresh in the bowl and dry, terribly stick in your throat dry, like eating shredded cardboard or something. The when it gets soggy it becomes a sloppy stew of just sloppy tasteless rubbish. {If you were making a movie with orphan kids back in the bad old days, show them with a bowl of soggy Weet-bix} The only answer I had as a kid was to dump sugar all over it.
Plus they have a really bad advertising campaign where they use notable sports-stars basically bragging about how many Weet-bix they eat and then ask the viewer "How many do you do??" Encouraging kids to load up their plates.