How do I actually use money from the Microsoft Account to buy stuff?

I tried on both the website and the console. The option shows up on the console but it's grayed out and I can't use it.

What is the cost of it? If you're in the US, the list price does not include tax, so you need to select a secondary payment method. On the next screen, it will ask you if you first want to apply the currency from the MSA. Then it will empty the MSA first
and make up the difference by taking money from your secondary choice.

Again, this can only be done on console.

You need to use the console to make the purchase, then it will show up as a valid payment method.

The Microsoft Account money is not yet compatible with the website, which seems to be what you're using.

I hope this help; let us know how you get on.

I've had my account for many years and have spent tons of hard earned money on Xbox and GFWL and new stuff on windows 10. I've been buying stuff since microsoft was first a company. How is it that a company with so much money and technology can't figure
out to let us play games from a few years ago? Makes no sense to me at all.

Since I buy allot of stuff from game stop, I have no problem from downloading the code like for example Skyrim Dlc from using xbox live points prepaid digital card from Game stop. But this would be my first time to buy stuff directly from Microsoft. I also
bought some stuff from Walmart with Paypal too. Paypal goes directly from my bank account automatic payment. Would this work by using Paypal. If so how do I do this. Thanks