While some housemates might be dreaming of new cars and exotic holidays, Big Brother's Sarah McDougal has more heart-wrenching plans for the $250,000 prize money – to pay off the debt her family incurred from her father's funeral.
"He was the smartest person I've ever met – he made me who I am today," the Melbourne student, 19, tells TV WEEK of her late dad Jimmy.
"He was 59 and pretty sick with emphysema, but doctors didn't realise how bad it was, so Dad pushed me to go on my first trip overseas to do volunteer work in Indonesia last July," she said.
"He passed away really suddenly and I got the call to come home as soon as possible. It was heartbreaking – and all the financial repercussions came down on us kids, so we got in quite a bit of debt.
"It would mean so much to me to be able to pay it off. It would change my family's lives."
The youngest of seven, Sarah grew up on the poverty line and got her first job as a dog walker at age 12 to help her parents pay the bills.
She was "distraught" when she had to turn down a private-school scholarship because the family couldn't afford to pay for uniforms or a laptop.
But the 149cm pocket rocket now feels grateful for her background.
"It's made me realise life isn't based on the money in my pocket," she says.
"It's the character in my heart and the drive to work for what I want, which has been a huge advantage in the house."
Of her plans for how to win Big Brother, Sarah says: "I want people to underestimate me, to think I'm that sweet, innocent, naïve little sister everyone needs.
"But in reality, every conversation and friendship I have is purely for my strategy."