If the fair market value of the car is really only $500, then the owner generally is entitled to $500 regardless of how much more it would take to repair the car. That is generally how an insurance company would handle a case where the repair cost exceeds the value of the car. The insurance company would "total" the car, pay the owner the fair market value, take the damages car, and try to sell the scrap.
You may want to check whether you will be charged by the government for hitting another vehicle and leaving the scene of the incident.
You likely should also check whether your state has mandatory insurance statutes.
Violations of these various statutes may affect your driver's license.
You should review your facts and options with an attorney.
Based on the facts described, you face both civil and criminal liability. Your civil liability equals the total amount of reasonable and necessary repairs limited to the fair market value of the car, plus any other consequential damages. Criminal liability may exist for failure to have insurance, for fialing to report an accident and for leaving the scene of an accident. I wouild advise you to seek a civil settlement with the carrier for an amount capped at $500 - the total value of the car, plus any consequential loss. Cross your fingers with regard to any possible criminal liability, but locate a criminal attorney in case the need arises.
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