I am working on a game right now, which I am dedicated to making free and for the most part 'open source' once its on the app store. But with the time I have spent on it I would like to open up some possibility of making some money on it. My idea is to have the game be free and unlock extra features of the game like 'Endless Mode' and probably 3-4 more levels of the game through an in app purchase. I saw on the App guidelines from Apple that you cannot include 'grayed out' or unclickable features in a game that require you to purchase the full version, but is it possible in the description of the game to say it has 'Feature A and B' but only through In-App purchase?
Here is Dizzypad HD's description: Their game is free and includes three modes for $6 of DLC, and their description says "In addition to the classic game mode there are three additional purchasable game modes that take Dizzypad to the next level!" So yeah looks like you can.
I actually used a greyed out button in The Impossible Test. The button is directly on the menu, and when you tap it, it prompts the user to purchase the feature. I've submitted numerous updates, and none of them have been rejected for having that button.
Well, The Impossible Test isn't the most "fair" example. It had the #1 spot for Top Free App for about a week at the beginning of April this year. It currently has over 4 million downloads, so we are happy with out numbers. If you can manage to get your app into the top 50, then your in for a VERY nice ride! Even now, almost 2 months, we are still in the top 50 and we still make more than enough to live off of it very comfortably.
From free games with IAP, I have seen many people spam 1-stars because they think they have been "cheated", and that the whole game should be free. Take Minisquadron special edition, great game, but in the reviews many people think it's just horrible for the devs to make them pay. For now, I would separate "lite" and full parts, just so people know what they are paying for, and if they pay for it, you know they had some inclination to get it. Note: I am not a developer, just an observer.