$50 Xbox Gift Card (Digital Delivery) - $40 (Can be used to buy Xbox/Microsoft hardware too)

Eneba has $50 Xbox Gift Card (Digital Delivery) for $40 after applying code X50US at checkout. If discount code fails, you can try guest checkout via private/incognito browser (You will be asked for email to deliver codes to at last step).
You can purchase the code(s) and redeem to add balance to your Microsoft account.

• Both the Microsoft and Xbox cards work just the same. Once redeemed to your Microsoft account, you can spend your balance at Microsoft Store online, on Windows, and on Xbox. You can get the latest apps, games, movies, TV shows, and Surface, Xbox, and accessories. (Source)

Add balance to your Microsoft account and use to purchase items from Microsoft Store online. For example, Xbox Series X for $396 by purchasing 10 * $50 Gift Cards.
 

Note:

• Price is after service fees and applying discount code X50US.
• Eneba codes usually sell out fast.
• Xbox Gift cards do not currently work at physical Microsoft Stores.
• You currently cannot buy Microsoft 365 with a gift card.