Are you a new driver? Are you planning to get your license? Are you under 21? You are in luck because there is a specific type of insurance made just for you. Yes you need insurance even if you still do not have your license. Remember that driving in the United States requires you to have insurance. Learning how to drive in a car is still driving. You can definitely take advantage of short term Car insurance under 21. This is just short term because you will be getting a different one when you finally get your license. You can set this up from 7 to 84 days depending on your need.
This should allow you to get yourself a car to practice on when you go ahead and start getting your hands on learning. This will not overlap the insurance the owner of the car got for themselves but it will assure them that their car insurance will not be affected in case you had to file a claim. Temporary car insurance works this way. You may also find yourself getting one if you need to add another driver for your car. This works on the same principle as the student driver insurance but the rate may differ according to the claims or driving history of the new driver you are adding.
The major reason why short term car insurance under 21 is cheaper is because of the claims that they file. It shows that the claims they file are bumps and scratches which does not raise any alarms with insurance companies. You should also consider continuing being a low risk driver by being careful all the time. It is always better to be safe than sorry for you do not know what may happen on the road the next time you drive.