I paid for full coverage in advance, but the rental company still tried to sell me their own insurance. I had to explain that I’d already bought coverage for the rental car through my insurance back home, and only then did they agree not to add theirs. This part can be pretty tricky if your English isn’t great. On the other hand, getting the toll package for $7.95 a day was actually worth it, because in California there are some toll or express lanes—if you accidentally drive into one, it’s really easy to get charged.