How many books do you have to sell to make a million dollars?
If you make $1 per book, you need to sell a million of them. That's not easy to do… but if you have 10 books, you just need to sell 100,000. How many books do you need to sell to make money? You need to sell almost 10,000 copies to just break even on costs. For a 80,000 word book you'd need to sell almost 60,000 copies to make an average amount of money for the time spent on the book.