What are /r/banddirector's favorite Products & Services?

From 3.5 billion Reddit comments

My students always enjoyed Tonal Energy. You are able to set the transposition and it displays the letter name of the note, but not notation on a clef. Plus the green smiley face is surprisingly motivating, even for the most stubborn of high schoolers. There are also plenty of extended features for advanced performers. It currently costs $3.99, so that may be a hindrance.

Unfortunately, I haven’t used android in a couple of years and I’m not sure if there are any better apps for your needs.

Amazon has these (and others) listed. Never got them because ordering from Amazon is a PITA at my school. Try hardware stores too, they occasionally have some.