I think the best pick out of freemium mobile vns would probably be Romance Club. Haven't been caught using aisloppa yet, have free diamond choices weekends which somewhat curtails the obnoxious freemium, the hack is 39 rubles per month, diamonds and cups both (no such thing for Choices' keys), newer books have prettier sprites, some stories are actually decent. Nile was fun outside of how hard they pushed Amen.

Might need to play in Russian, though. I've heard translation sucks ass.