As on all the other platforms, FIFA 14 for Windows Phone 8 is free to download. There are, of course, IAPs available for those that want them.
You won't need these IAPs to play the game, mind. Just to unlock extra cups, competitions, and packs of players.
In our review of FIFA 14, we said: "A typically polished footy game with a surprisingly generous freemium model. But EA needs to improve the way it plays touchscreen football if it's to keep the paying punters happy for FIFA 15."
You can download FIFA 14 from the Windows Phone Store now for free [download].