I think right now their demo is using QR codes. I don’t think the jump from QR to NFC is that difficult but I could be wrong and I don’t know what their pipeline is at the moment.

You could look at the Taler Project. It is still probably years away from becoming usable but it is a really interesting and promising payment system.

The docs are outdated. They are currently releasing once a month. There is an issue on their github here to update the documentation

AdAway for rooted devices allows you to modify you hosts file directly. This means that AdAway doesn’t have to be constantly running in the background to block ads. It modifies the file then closes.