Hey Ash,
Most South African authors have what is termed a day job, it is sad but the numbers in this country who read are particularly low. Enough so that if a publisher hits that 3000 mark they are super excited.
As an example my first print run for Lolly was 15 000 considered a high number. Now it doesn't seem that way but it is estimated that only 3% of the population actually reads.
Now take that and put it at 1% of those actually buy the book the rest loan it from a friend.
As an author your percentages are around 10% of net increasing up on numbers sold.
50 Shades and the rest went viral and that is when the money comes into play. You have as much chance of winning the lotto of that happening on a global scale.
As for the book on Lolly it was a mix of personal experience and massive research in order for us to give an all round story.
books.google.co.za/books
Regards
Sean