Anecdotally, I like what the developer of Blink Shell[0] has done. The app is 100% free software[1] under GPL3, so you can easily build it yourself with XCode, upload to your phone, and use as usual from there, which isn't a big hurdle for the target audience. But I bought it. At the time IIRC it costed 20 bucks on the App Store. I bought it because it was incredibly frictionless to pay the money (Apple is good at that), and it felt good to support the developer of a tool I liked and used.
So it leaves me wondering, where are the big obstacles. All other things being equal, I will choose a free/libre solution, but we know things are far from equal.
