You have to do the sums. Say the CX-5 is £25,000, that makes the deposit £12,500. If they put a GFV (guaranteed future value) of £10,000 on it, then, though you're 'financing' £12,500 at 0 per cent, you're only actually paying back £2,500 which, over 36 months is a mere £70 a month. But, having added your £12,500 deposit, what you are really paying back per month is £417. And then, to keep the car at the end, you have to fork out £10,000 on top.