I was born in 1988 and learned this version as a kid in the 90s:

Crazy? I was crazy once. They put me in a rubber room and told me to get a life. Life? What's life? It's a magazine, costs fifty cents. Rats, I only have a quarter. Rats? Rats drive me crazy!

I have a feeling we may have substituted "it's a cereal" since that was a better cultural touchpoint for me at the time.