The glamour model - who has her own range of clothes, books, perfumes and bedding - has always been keen to earn cash and is forever coming up with ways to boost her wealth.
Katie - who has an estimated £45 million fortune - said: "My mum`s friend gave me the Kylie song `Tears On My Pillow` for my 12th birthday and I also got a tape recorder so I used it to record that song and others off the radio and sell them for £1. I`ve always loved the thrill of makingmoney."
"I was very shrewd from a young age. I remember going to a pet shop with my mum aged about nine and there was a black rabbit that I desperately wanted but she said `No`. I thought to myself, `I`m going to have that rabbit`, and when we got home I found Mum`s cheque book and wrote out and signed one in her name for the price of the rabbit.
"I posted it off to the pet shop and they phoned back a few days later and asked to check some details with my mum. I was grounded for a week."
While Katie - who is also known as Jordan - has done well for herself, she refuses to be flash with her money.
The mother-of-three told The Sun newspaper: "I`ve got a lovely home which I`m very proud of, I drive a nice car and I`m able to pursue my horse-riding hobby. But my kids still go to state school and my motto is `Don`t flash the cash`.
"When you come from a background of no money there is always part of you that thinks you could go back to that place. I like to think I`m generous but not stupid with money."