Call your insurance provider with this question. Most offer a grace period to cover a recently purchased car until it can be officially added to the policy.
If you tow it or trailer it, you won't need insurance. Rent a tow dolly. If you drive it, you will need insurance. You can't buy insurance for one day.
No. I don't know of ANY insurance company who would write an automobile policy for just one day. If you're going to buy a car, you'll need to insure it before you can drive it on public streets anyway. Why not just buy a regular insurance policy?
Maybe. One way is that you can insure it for a minimum term (6 months?) and then cancel it after one day.
BUT...........Do you have another insured vehicle? If you do, the insurance for that one may extend to the newly bought vehicle for the drive home. Instead of asking here, you should be asking your present insurance agent how to proceed. or.....any insurance company if you don't presently have an insured vehicle
I don't know why you would want to insure it for a day. When you inspect the vehicle, get the VIN and call your insurance co and tell them that you are going to buy a vehicle and you want insurance on it starting on what ever day.
You can call and get insurance started before you drive home. This is with both existing or new insurance. If you can't afford to do that, you can't afford the vehicle.
Simply provide your insurer information regarding the two automobiles you are considering. Also tell your insurer the date you will likely make purchase. The insurer can activate the policy on any date you choose.