Multi car insurance enables you to insure more than one car with a single policy. With certain insurers you can insure up to 5 different cars with the same car insurance policy provided they are registered to the same location. With this in mind you could possibly insure cars at your home for your children, spouse etc.
A multi car insurance policy can, in theory, save you money. This is down to the fact that you are essentially bringing more business to the car insurance company and making it easier to bill etc just as a telecoms provider would give discounts if they supplied phone, internet and television. In other words it’s like buying car insurance in bulk.
It’s always worth looking into both options as sometimes multi car insurance could work out more expensive.