I got scammed on the App Store a couple of weeks ago. I needed the SmartThings app for some Samsung home automation devices, searched for it, and installed this one: https://apps.apple.com/us/app/smart-things-smart-view-app/id... When it charged me a $20/year subscription (now cancelled) I thought "Wow, Samsung charging me for this feels pretty cheap of them, but I guess that's how they do things - after all, I found…
I've also seen the "free but not free" apps like in the twitter thread. Usually there is an invisible "X" in the top corner of the payment form that you can click to get past it and use the app's free features after all. My kids run into these all the time: they see an ad for a game, it has good reviews so I let them get it, it prompts them for payment. If you are clever you can sometimes get around it, but I've seen cheap old arcade game knock-offs asking for $30+/mo! This is not by any stretch the only developer making mad bank on a subpar app.