Unlike many states, California offers a way to return a used car, but it is —you must purchase it as an add-on. Car Buyer's Bill of Rights - California DMV - CA.gov

: You have the right to have a vehicle inspected by your own mechanic before purchase.

2. The Contract Cancellation Option (The "2-Day Cooling Off")

California law mandates several disclosures and standards before you sign a contract: