I have written and illustrated 2 books to encourage music practice available on Amazon and my website. "Have Fun With Your Music" for young musicians and "Passion For Practice with Musings From Music Masters" for all ages.
I make violin/cello/bass purses or bags which are fun to use as purses, but also are used as string player gig bags. The back pocket fits the largest size cello string pack, the inside can fit a small metronome/tuner, a shoulder rest, rosin, eye glasses, cell... and comes with a small leather wallet. I have also created Piano bags and guitar bags. There are many more creative whimsical products at MusicTeacherGifts.com. (Including whimsical music themed greeting cards with practice tips on the back.)
MusicTeacherGifts.com holds an annual youth composition competition.