Most of the time, Google Maps is great. You know when it's not so great? When a data connection isn't present. In fact, it's basically useless without some form of data. If you're ever in a situation where you're 1) low on data, 2) without a connection, or 3) roaming, and need to find a way to get from A to B, then a good offline solution is clutch.
One such solution is Sygic GPS Navigation, which is currently on sale for up to 70% off. The best deal is by far the World package, which is currently going for $37.49 USD - a savings of about $87. The World package includes a slew of European and North American countries, including all of the United States and Mexico. You can see the full list of covered areas here. If you need something a little more focused (or a little less broad, depending on how you want to look at it), the Europe and Russia pack is also on sale for 70% off, which knocks the price down to about $24.99 USD.
Other packages are also on sale: Australia and New Zealand for $37.49 (25% off), Europe for $24.99 (60% off), North America for $24.99 (50% off), Brasil for $24.99 (50% off), along with a few others. You can find the whole shebang on Sygic's site.
The best part about Sygic is that once you buy a license, that's it - updates are free for life. That means that no matter where you are, you'll always have the latest maps available, regardless of your data connection at the time. That's reassuring.
Alongside always-available maps, Sygic also offers a slew of premium features, like dynamic lane guidance, junction view with lane indicators for tricky intersections, speed limit warnings, a cool heads-up display mode that effectively turns the vehicle's windshield into the navigation screen, and more. It's also the first navigation application to offer dashcam functionality, allowing the phone's camera to be used to record the road ahead while navigating.