This is the #1 tuning app that we recommend for anyone with an iPhone, iPad, or iPod! It is a great tuner and metronome that only costs $3.99. It also allows students to practice with a drone pitch sampled from the instrument they play, which is a great way to practice playing in tune with others, and it has the ability to help them tune chords using just and equal temperament.
Every band student with a smartphone should have a tuner app on their phone. Making sure your instrument is in tune before a rehearsal is very important, and since most students have smartphones or similar devices, there should be no excuse for not having a tuner.
insTuner Free is a free tuning app for iOS devices. It is not as feature-rich as either of the two at the top of the page, but it gets the job done! It can be found HERE.
gStrings Free is a great free tuner app for Android devices. It is not as feature-rich as the recommended paid apps, but still has some great features and will do the trick if you need a free app.
For those who want an actual physical tuner, the Korg TM-50 is a very affordable Tuner and Metronome combination. It is available from Musician's Friend, and from local music stores such as Gordon's Repair Shop in Boardman.