With a PCP you put down a deposit and a fixed 'guaranteed future value' is put on the car. You then make monthly payments which pay back the difference between the deposit and the future value, with APR interest on both the difference and the future value. When you get to the end of the contract, you can buy the car for the guaranteed future value, use any equity in it as deposit for another PCP, or walk away. Quite a lot of PCPs become 'toxic' because the guaranteed future value turns out to be far more than the true value.