With my deals, you get a brand new car with zero miles on the clock, delivered to your door. The new car is fully taxed and has the full manufacturer's warranty and AA cover.
It has proper New Car Smell; you know this smell? MMMMM! You then run this new car for 12, 18, 24 or 36 months depending on the term, and run it within an agreed mileage limit (usually 10,000, 15,000 or 20,000 miles per year).
If you exceed the mileage limit, you pay for extra miles at (typically) 4p - 10p per extra mile. This is known as the excess mileage rate.
Local franchised dealer will sort out any warranty problems for free, but on most contracts (except VW group) any VAT registered garage can service car very cheap. Mainly, you can avoid manufacturer agents, they are damn expensive.