Student or Learner
"Is it possible to live off that much money?"
It's my understanding that "live off" is better suited for informal contexts, whereas "live on" is preferred in more formal English. Is this the case? Or am I wrong?
You can live off the land (neutral), your parents' money (disapproving), hamburgers and chips (disapproving).
You can live on hamburgers and chips (disapproving), a hundred pounds a month (neutral), that much money (neutral).
The adjectives in brackets describe the probable attitude of the speaker using those expressions, in my opinion.