The following are limit time promotion during 6/13-6/30:
✔ Free to students
1) Find a spell, a syntax error or an inappropriate sentence from my app, guide (on blog) or the description in Android Market(I think it's easy, because English is not my mother language);
2) Or find a bug from my app;
2) Send your findings and prod code to me with your edu mail, each mail can request one key.
✔ Free to normal users: post recommendation or introduction article (>100 words) to forum, blog, Facebook, or other public sites, then send the link and prod code to me.
Prod code can be found in Menu > About or Menu > Buy
Mail to: email@example.com