Thanks! I'm still unsure about how to price it. Considering the time you have to commit to learn anyway, and comparing to textbooks, $9 is cheap for me. But on

Thanks! I'm still unsure about how to price it. Considering the time you have to commit to learn anyway, and comparing to textbooks, $9 is cheap for me. But on the other hand, since most people are used to $1-2 for apps, I'm not sure how well it will sell. I'm happy to hear that at least for you it doesn't sound too much.