Don't even bother trying to get every card in the game. Even when throwing thousands of $$ in there you will not get them.
It'0s actually imposible to have all the cards.
Why? Because later on new events will be added, like PeroPrincess, where players are divided in 2 or more groups (Princess has you choose one of 3 gals), and every group gets a different limited reward card, of which some get re-released through e-gacha, but others don't