Why would it be expensive?
Of course, choose your power supply badly and both those sub 10W machines will be 50W at the wall.
Their free tier is pretty generous because it's basically a way for Tailscale to get homelabbers hooked on the product so they'll recommend a corporate plan at work. They even state as much: https://tailscale.com/blog/free-plan
The Pi 3 was essentially free to me because I already had it on a shelf. When I duplicate this setup at some other relatives' homes, I'm planning on using an Orange Pi Zero 3 ($30 CAD, quad core A53, gig of RAM, gigabit Ethernet).
- You're replying to a thread about someone using a 1GB Pi 3 to stream multiple 4K movies. It's $44 on Amazon including fast shipping. Cheaper on eBay if you can wait 3 days.
- The 8GB Pi 4 is $75 on canakit, not $160.
Anyway if you want more compute (on an edge device? why?), why not grab a AM4 board and CPU for like $80 each? That's 25W at the wall and gives you a ton of flexibility if you later wanna repurpose the machine adding GPUs, NVMe, SAS enclosures, etc
To be fair once you add in shipping, a sd card card, power supply, case/heatsink, and you'll get to around 160.
Why would you need a heatsink unless you use a case? Why would you use a case? That price tag is entirely self inflicted