How do you feel about the model used by League of Legends? The overwhelming majority of content is sold for virtual currency (read: cash), but you can always pick what you want. Loot boxes in League are given out as prizes for playing exceptionally well, and the keys that unlock them, though sold in the store, are given out as bonus rewards free of charge to players via the in-game honor system (were you a good teammate, did you not complain when you lost, etc.). Similarly, the Halloween event (ongoing) gives random loot boxes that don’t require keys to open as rewards for completing certain objectives, but there is no incentive to throw down for 10 (or 50, or 100) loot boxes when you could just purchase the content you want instead.

In short, if there’s something you very much want (and I confess, I own a $30 skin and am happy with it), you pay the price asked. Every once in a while, you might be able to get something via a loot box, but they are not what’s being primarily advertised in the storefront (though they are for sale, as are the keys — I have spent hundreds on the game and never bought either).