The bare minimum penalty for driving a vehicle without proof of insurance or proof of financial responsibility is a fine of $100 to $200. This, however, is up to a judge's discretion.
Many states have been ramping up the penalties for driver's not obtaining the proper insurance for their vehicles. California, in particular, is one of the least tolerant of states on this issue. Once a driver receives a ticket for not having proof of insurance, they must pay a financial penalty of at least $100 for the first offense, and $200 to $500 for any subsequent offense within the following 3 years. This does not include court costs imposed by the judge, which can also total hundreds of dollars.
Some states allow a driver to bring evidence that they had insurance at the time of the ticket and will waive any penalties. California will assess at least some financial penalty in these circumstances, reasoning that keeping these documents in the vehicle is part of the driver's responsibility under the law.
Additionally, a judge has the power to impound the vehicle and revoke driving privileges. In this instance, the vehicle is only retrievable after the individual pays all towing and impounding fees on top of providing insurance. Reinstating driving privileges varies depending on the judge's orders and can impact out-of-state drivers also.