T-Mobile had already launched its Galaxy S8 bogo offer a week or so ago and now Samsung joins in with one of their own. However, T-Mobile still has a role to play in this one as well, since at least one of the two smartphones needs to have an active T-Mobile line in it for the user to avail the offer. You can use the other one with whatever network you wish though; something that is not a part of the bogo deal offered by T-Mobile earlier. However, the activation of the T-Mobile line has to be done through the official Samsung.com website.
The deal is valid for both the Galaxy S8 and the Galaxy S8+ and once you have activated the T-mobile line, Samsung will refund you $750 within 7 - 10 business days via the same mode of purchase as used by you. As far as I know, the offer can only be availed via Samsung.com as of now. In case you are wondering what's the catch here, surprisingly enough, there doesn't seem to be any really! Samsung will not refund you the money through monthly rebates or via a prepaid card of any kind; instead they will return up to $750 directly to your credit card/bank account, depending on how you bought the two phones form their website. It's a great offer and will possibly last for a very short time.