An Apple developer's license costs $99 per year.
To get your game published through YoYo games, it has to be up there, the best of the best of GM creations get published. I'm not sure if you can simply submit your game for publishing.
Should you own a Mac, you can develop and deploy your own games for iOS using the native language or another engine.
iOS development will be supported in Game Maker Studio, which is expected to be costly - it will only be available on Windows.