Sadly, game is not 100% free. Only a few songs are available. If you love the game and want to support it, you can buy more songs and unlock later chapters in Store.
I am not sure whether this is a problem to you guys or not, but the game can only be installed in Internal Storage (a.k.a. Phone memory). There is no way to move it to External Storage (SD card) and this is surely a big downfall to me.
All in all, Lyrica is a great game. Highly recommend for rythm game lover.
P/s: Does anyone know how to open Missions? My wifi is on and I have tried lots of way, but the game always refuses me to earn more songs through Missions. Unlucky me