It doesn't sound like you purchased it from a dealer. If you purchased the motor vehicle from a dealer, the state's registrar must give you temporary registration plates that last for 20 days. This is to give you time to register your vehicle, get proper insurance and the like. If you buy it from a private party you are not getting the same benefit and in fact, once the transfer occurs, that seller's registration is automatically terminated and you must register your vehicle prior to driving it. This is on the off chance you get in a car accident and of course to prevent unlawful or fraudulent transfers. In every state that require motor vehicle insurance you must actually have both proper registration and car insurance before being able to take a motor vehicle off the lot.