I'll be visiting Cancun in about a month with my wife and her parents. We'll be staying at a timeshare outside of Playa del Carmen so I'm planning to rent a car to maximize our ability to get around. I have a few questions about insuring the rental car:

- What level of insurance should I plan to buy?
- Is it reasonable to buy insurance ahead of time, from an agent in the USA?
- What's a reasonable ballpark cost?

Thanks in advance.