The announcement from Apple this week concerning textbooks is coming where they say they will announce a "Garage Band" for textbooks app on their platform. If you want to know more, this arstechnica article is the one that seems to be getting the most attention.
If you have Windows 8 in your lab. you'll want Music Maker Jam - a sort of Garage Band" for Windows 8. It doesn't seem to have the complexity but it is a great thing for creating and has a whole different feel. Install it in labs for students to mix their own music.