Wait what? How does this work?
As long as you
don't have an active Game Pass subscription of any kind. That includes one that has been cancelled but your time hasn't run out yet.
1) Get up to three years of XBL Gold codes from anywhere
2) Go to Xbox website
3) Top up your Xbox Live Gold to a maximum of three years/36 months with the codes, and don't turn on "auto-renew" for the free month.
4) Select the option to "Upgrade" to Game Pass Ultimate
If it's your first time doing it, they'll give you a 1:1 conversion of your XBL Gold time to GPU time for $1. If you've done it before, they'll still convert it at 1:1, but you'll be charged $14.99 for the conversion instead of $1.
So if it's your first time, even if you paid full price for three years of XBL Gold codes, you're getting three years of Game Pass Ultimate for $181. If it's not your first time, it's $195.
That works out to paying a little over $5 a month for Game Pass Ultimate, and you don't even have to think about it again until November 2023.