The ultimate dad move happened today
Took my 5 year old to the grocery store and he asked for cereal. I pointed at the store brand box and said 'That's the same cereal, just in different clothes.' He actually believed me. My wife nearly lost it when we got home. I'm calling this a parenting win even though it's probably not.
I respect the financial wisdom here but I also respect that your kid will remember this moment forever. Could be a funny story someday, or could be why he buys premium cereal as an adult act of rebellion. Either way you're winning.