The Signal messenger and protocol.

I think this is reasonable and good. It helps fund the foundation, and if someone is that concerned about their privacy then its fair for them to give some tiny support to the developers making it possible for them. It will really all depend on the price whether this is unfair or not. As long as its something that even our very impoverished third-world friends can afford, I think this is a good win-win.

Ah good they've finally decided to implement the thing we've been asking for for a decade

Xmpp?