FLY is FUN

Hello, Im tried to install, the app, on my friend samsung galaxy note, but it said that de trial version has expired. why is this, someone does install the app, before.
If he want to buy the app, how do you do, because it when I clik buy, it automatic redirecction to the app fly is fun unloccker and I dont if it ok.

thank Agustin
im from argentina