Xbox Game Pass Ultimate is only $1
Xbox Game Pass Ultimate is a new subscription option that gives you Live Gold and Game Pass for one monthly fee. With this deal, you will get the first month of Ultimate for $1, plus it will convert any remaining months you have on your existing subscriptions to Ultimate (up to a maximum of 36 months/3 years).
For example, you currently have 6 months of Live Gold. Sign up with this deal and get 7 months of Ultimate ($1 for first month, 6 months of Live Gold converts to 6 months of Ultimate).
Second example: you have 9 months of Xbox Live Gold left and you have 6 months of GP left. First month for $1 + 9 months + 6 months = 16 months of Xbox Game Pass Ultimate.
Additional tips below.
Once subscribed/converted to Ultimate, if you go to the Xbox website, you can turn off recurring payments if you don't want to pay $15 after your sub ends.
Potential way to maximize your $: The longest possible Xbox Game Pass Ultimate subscription is 3 years. If you can find Xbox Live Gold or Game Pass deals for cheap, buy enough so the total of those plus your current remaining months <= 36 months. Redeem all those codes, sign up for Ultimate, and get 3 full years of Ultimate.