Financing a used car
A car used or new is a big investment and you may want to use finance at least in part to pay for it. Of course the less finance you use the better, putting some cash down will instantly lower your interest rate for finance and you can also trade in an old car and just use finance for the difference. The car will usually be the collateral for the finance so the lower the amount you borrow is relative to the vehicle, the lower the finance companies risk and so they will give you a much lower rate. Even if you have a poor credit rating paying a proportion of the value will bring your rate right down. You can of course get no money down refinancing and even with poor credit. You may well need this if your old car has given up the ghost and needs replacing but has no value, or if you need to buy a car for the first time or need a second car or other vehicle for the family.
Not everywhere will offer zero down deals mind you so you are lowering your choice of places to buy from. You may even want to consider other finance options anyway including loans and credit cards that could be unsecured or which you could secure on other property. You could even look at increasing your mortgage to get some extra money. The interest rate is the important thing and generally the lower the better but if you can get money somewhere that allows you to buy a cheaper car including if you buy privately this may be better value.