ASA Insurance has picked up contracts to supply cover to new customers through KIA and MG Rover dealerships.
The broker said it was accepting business at all of the UK's 135 KIA dealerships and 289 MG Rover outlets.
ASA Insurance chief executive Simon Clayton said: "The interest from KIA customers has been fantastic - so far we are doing about 40 cover notes per day.
"This also means we have 40 fresh customers to target."
The MG Rover deal, which started on 1 July, will run for three months, offering free insurance on all of the manufacturer's small and family cars.
The deal requires customers to meet certain criteria for cover, but if they fail, other providers will be found.
Clayton said: "Manufacturers are finally starting to wake up to the fact that they need to be looking at free deals rather than price agreements."
ASA has insurance arrangements with about 900 dealerships across the UK covering a wide range of manufacturers, including Ford and Mitsubishi.
Simon Clayton has also been appointed non-executive chairman at LFC Insurance Group, which is run by brother Jerry Clayton, following the death of Derek Mitchell.
