alt Hacker NewsEh but that's a commercial tool. They don't even seem to have a free community version. I wouldn't pay for that. And prefer Firefox anyway.
For remote browser tools I use neko https://github.com/m1k1o/neko
But with Tor I like to have more safeguards. So I prefer to run tails in an isolated environment.
You're right that BrowserBox is a commercial product and there's no free tier. Honestly, the reality of running remote browser infra and development is that a free version just gets instantly hammered by botnets, scrapers, and abuse. Keeping it paid is the only way to be sustainable.
I see Neko brought up a lot, but honestly when I tried it a couple years ago it felt pretty clunky. It seems designed more for anime watch parties than serious security or remote isolation, IMO.
I totally get the Tails/Firefox preference, tho. If you want absolute baremetal isolation on your own hardware and have the discipline for it, a fresh Tails USB is definitely the right move. BrowserBox is just a different architecture -- it's mainly for when you specifically want an ephemeral Chromium setup on ... well ... anything, need some policy controls or programmability. And don't want to fiddle with config yourself.