Z is for...

Zero per cent

Not strictly an optional extra, but zero per cent finance is well worth having. The base rate of interest is currently rock bottom, but most lenders haven’t passed the benefits on, and loans tend to cost much more. So paying no interest is a bonus and could save you thousands of pounds over the course of a finance agreement. 

Most deals require a minimum deposit, but don’t forget that any car you part-exchange will count towards this. As the finance rate is usually subsidised by the maker, you’re still free to haggle on the car’s price. Plus, with no interest, your monthly instalments will be smaller – so you’ll have more money to spend on extras...