4. Skip the expensive cabs
MetrO: Free for iOS
Up there with breaking through the language barrier, deciphering the mass transit system in an unfamiliar place can drive you crazy. Instead of caving in and shelling out for an expensive cab or car, use MetrO to navigate the trains, trams, buses, and subways in over 400 global cities. It doesn't even require a network connection as long as you've installed the city you're visiting ahead of time.