Thief: Gold, PC – Free
Registers on Steam
Head to this page to get a coupon which will knock the price down to free when you purchase Thief from Amazon.
To purchase digital games from Amazon US, use your UK Amazon account, and add a US billing address to your account. This address needs to be a valid US address, but nothing will be sent there, and you can access all your games through their website. Some card issuers may charge a fee.
Cheers Sam for the tip off.