With this voucher.
Green Man Gaming just sent me an email to save 30 percent off FIFA 16. Here's what they had to say:
FIFA 16 is out and brings a whole host of changes to the series, including advanced AI, dynamic crossing, women’s national teams, and all new 3D player modelling and animation. Get 30% off with our special voucher, just for you!
Add FIFA 16 to your basket, add the 30% off voucher above at the checkout, and save now. The beautiful game has never looked better!
Since FIFA 16 has a list price of $59.99, that voucher brings that cost down to $41.99. Please note that Origin is required to download and play that title.