WinGameStore (extra 5% off with code "pcgames5off")
https://www.wingamestor
Gamesplanet
https://uk.gamesplanet.
Yes, sites are legit .
Per the comments via Gamesplanet this is a global Steam key.
Also per Gamesplanet:
If you own MGS V: The Phantom Pain and purchase Metal Gear Solid V: The Definitive Experience at Gamesplanet.com, you will receive a giftable copy of MGS V: The Phantom Pain for your best friend!