The NET translation (bible.org) is widely used in free Bible apps, so while it is not public domain, it seems to be free. It's a nice translation, and also has

The NET translation (bible.org) is widely used in free Bible apps, so while it is not public domain, it seems to be free. It's a nice translation, and also has lots of notes (if the app provides them). The ESV translation has a free app, too, although that might not help someone trying to add it in their Bible app.