It is recommended to rent a car or use ride-sharing services during your trip to Monrovia, as the town's attractions are spread out. Travel costs vary depending on distance and traffic, but expect to spend approximately $80-$100 on transportation for the entire trip.
If you have more time, consider visiting nearby attractions such as the famous Santa Monica Pier or the Getty Center museum in Los Angeles. If you have less time, prioritize and choose your favorite activities.