Thank You Satan (1989)

Nathalie Monnier is 14, her parents are splitting up, and what's worse, their apartment is going to be put up for sale. Just about everything in her life is about to be shattered. So it makes a bit of sense that she is receptive to the possibility of selling her soul for the chance to keep all this from happening. Just as her parents are (of course) getting back together, she wins the lottery and is able to buy their old apartment.