Required Apps 
Charms Blue (iOS - Android) - Free and required: We will use this app to keep up with finances, handouts, music files, and recording playing tests.
Any Chromatic Tuner - InsTuner Lite - Free: Tuner that works great!
Any Metrnome - Metronome - Free: Metronome that works great!

Suggested Paid Apps
Tonal Energy - $3.99 - This app offers equal and just temperament tuning, tone wheel, piano, guitar, recording, sharing of recording, recording manipulation, spectrometer, amplitude graphics and ...too much to write here. Get this for a fantastic tuner and metronome combo.
Staff Wars (iOS - Android- $.99: An excellent and fun note naming game.

Suggested Desktop Apps 
Staff Wars - Free.  (PC/IOS) An excellent and fun note naming game.
Staff Wars 2 - Free.  (PC/IOS) Students must play the notes on their instruments to win at this note naming game!