Not the person that created this thread, but I've had a bunch of music education apps in the App store for a couple of years. I get a decent amount of downloads, enough to make $60-$120 a month. I sell them outright for $3.99 (Canadian). I actually found I increased sales when I increased the price, I used to sell them for $2.99. I haven't checked recently, but there weren't many high quality music games there, mostly basic looking drills that weren't themed. I'm sure I could increase my sales if I was savvy at marketing and had the resources to commit to it.