I'm currently tinkering with a project that is based on the gameplay of Zelda: A Link to the Past (an adventure game where character upgrade is made through the acquisition of new powers which have tangible effects on your surroundings).
The problem is that I'm to make this into a Free-To-Play game, and I'm not exactly sure what mechanics to introduce to make it happen.
I mean, sure, I could just say: Let's make the "bomb/arrows" scarce and let the user pay for more, so that lazy players will pay us money.
But I don't think this would work much, nor would it be an interesting mechanic to work with as a developer. It's not satisfying for the players either.
I want something that players can grind for free, if they so choose, but that can be monetized by impatient players.
Customization came in mind, but given that this is 2-4% of gross sales in F2P market, I doubt the game would make significant sales with that.