Just as as I said, it's CLEARLY NOT AGAINST LAW to drive somebody else car, just as anywhere in the world, if you drive it, you must be insured, but there is of course NOWHERE IN THE WORLD (except maybe North Korea?) where you can drive someone else car if you are not insured.
So ridiculous to even think that it's possible.
And no, multi drivers insurances is not so expensive except if you are really poor, but then you should not own a car.