I just created a page on itch.io for Opt Out. Just like on my website, it's available under a pay-what-you-want model.
https://rory-price.itch.io/opt-out
I've been using them a lot to buy video games, and I always appreciated how they allow me to purchase without having to make an account. I figured I'd take advantage of their book section. If you or someone you know likes to buy from itch.io, the option is now available.
