Google Maps isn't just for getting to one destination. Once you have set one destination, you can tap the "..." symbol to open a dropdown menu and tap "Add stop." However, Maps only lets you add up to ten stops. Also, none of the stops are optimized for traffic or total length of driving time. Instead, they simply appear in the order that you enter them.
This lack of route optimization is a major downside to the free app, and puts it below the ten paid options on our list above. As always, you get what you pay for.