I'll tell you an amazing service that used to exist but stopped.

Snapcard.io is currently a wallet website, but used to be something completely different.
It has a bookmarklet which you could click on any webpage and then choose an item on the page that you wanted to buy.

It would take you to a snapcard.io payment page where you would pay the price of the item + a small fee. They would have a wide array of payment methods available and would hence buy the item for you and accept your BTC.

It was just amazing. It would work for anything, steam wallet, amazon, ebay, etc. And would allow you to spend Bitcoin on pretty much any online site without them accepting Bitcoin.

If you can somehow create a service like this again, I'll be your first customer