CDKeys has 3-Month Xbox Live Gold Membership (Digital Code) on sale for $11.79.
Conversion to Game Pass Ultimate:
- New/Expired Subscribers: 1:1 conversion if you redeem XBL Gold first then join GPU.
- Existing Subscribers: The message on the screen during redemption says a month, but you will get 50 days.
Note, you can stack up to three years of Xbox Live Gold or Xbox Game Pass Ultimate.