Yes. For that one car, you would normally have to turn in your tags and registration if you no longer carry at least the state's minimum liability insurance on it.
State laws vary, but most require that car insurance coverage be maintained throughout the entire vehicle registration period, whether the vehicle is used or not. If you cancel your coverage on any of your vehicles, then you will need to turn in your registration and license plates to your Department of Motor Vehicles (DMV) for that vehicle.
If you fail to turn in these items to the DMV, you could face penalty fees for a lapse in insurance. In some states, you may receive a suspension of your vehicle registration privileges as well. If you were caught driving without insurance in this car, then you could also have your driver's license suspended by the state.
There are a few states where you do not have to turn in the plates if you take insurance off of a vehicle that you are not using. But in these states you need to fill out paperwork with the DMV regarding the planned non-operation of your vehicle, which part of it states you will not operate the vehicle again until insurance is placed back on it.
The car insurance you kept on your other two vehicles does not extend to the vehicle which you took insurance off of and thus doesn't help you in any way. If you took auto insurance off of your third vehicle due to cost but still would like to use it, then shop around to find cheap car insurance quotes.