BillyGoat is free to use, including the following features...
Detailed offline mapping for every state and territory. Most other apps charge over $100 for this feature alone.
See your location on the map along with moving map features
10,000+ Interactive POIs such as Campsites and Caravan Parks
Pins to mark Points of interest
Import GPX files
Premium features which require a subscription unlocks...
Get Directions to your destination
Monthly map updates
Backup and restore your trip data
A subscription costs $27.49 AUD per 6 months
The app is very functional even without the premium features. However a subscription unlocks the full experience. A 7 day trial is included so you can experience all the features without any risk. You can also cancel anytime. https://www.imore.com/how-to-cancel-app-store-subscription-ipad-iphone-mac-apple-tv