It depends on your skill level.
But really, if you want to play a song, just get your mind set to do it.
It's much easier to play something you like than something easy but you don't really like it.
Find a song you love, maybe a theme song from a movie? Something you heard when you were little? Anything, as long as it's what you want.
How is this a shortcut?
Well, most of the times, piano teachers will force you play certain songs/exercises you don't like.
In my opinion, it's really painful to learn it that way.