This mapping app uses an extract from the free OpenStreetMap on a country by country basis. The Google Android free version of this app has a limit on the number of built-in map downloads, and the paid for version removes the built-in limit. There is also an Apple iOS version of this app here. Further details on the app can be found on the OsmAnd web site here.
Here are example screenshots showing roads, footpaths, gpx track, map downloads and numerous other features supported by the app:
The maps are stored on the phone and so do not require a data connection when you are out and about. For further details on obtaining and using free OpenStreetMap extracts with this app please contact Chris Young or Leon Fotiadis.