Need to review, notes, rhythms, key signatures, rhythms, or simply want to know more than all your classmates? MusicTheory.net offers great tutorials over the material you need to succeed in band class. Click the button to go there. They offer an app of their lessons too.
Download the Tonal Energy Tuner "TE Tuner" to your phone or tablet. It is available for both Apple and Android. It is a pitch generator, tuner, metronome, articulation analyzer, and more! This is an essential practice tool. We use this frequently in class, and it is important that you tune yourself independently at home and practice with a metronome.
Bandmate Chromatic Tuner - Free and easy to use, this app only does one, incredibly useful function. It tells you what note you're playing and shows it to you on the staff (the sheet music). It also tells you if you're playing it in tune like other tuners.
Above all, Rhythm Cat is an entertaining game with a great soundtrack to play along to, but it also has the added benefit of teaching you how to read the most commonly used music rhythms, with levels that build up progressively. A fun way for beginners to get past the most challenging and often discouraging introduction to reading music. Developed in collaboration with professional musicians and educators. "Lite" is the free version. More levels exist in the paid Rhythm Cat and Rhythm Cat 2.
The free metronome app called Pulse is simple and the most user-friendly metronome app we have found because you simply swipe around the circle to increase and decrease tempo, and tap to start and stop it. If you want to get fancy, you can choose the color of the pulse, choose from 8 different sounding clicks, choose 8th note, triplet, or 16th note subdivisions, or tell it to vibrate the pulse for you (this is the "haptics' option).