I‘m not sure about the $30. but look at the Fujitsu Futro S740. They can be had for about $50 with 8gb of ram and an included ssd, have support for dual 4K monitors and so on. No WiFi out of the box, but they do have a second m.2 that can be used with a cheap WiFi card if that is what you need (or you could install a second ssd).
It’s pretty good ddr4, but okay. You can have 8Gb of ddr4 for another $20. Not exactly a bank burner for a server or client.
How about the other features? Does that 8GB ddr3 computer have dual band wifi? Dual monitor 4k support at 60hz? Native hardware hevc/vp9 decoding?
Id love to see a link to these $30 PC people are talking about. Even older SFF aren’t going for $30 generally, unless youre buying in lots.
Can you beat a raspi 5 with a recent-ish SFF going for $200? You bet, but that flips the “pi is bad value for the money” on its head.
I‘m not sure about the $30. but look at the Fujitsu Futro S740. They can be had for about $50 with 8gb of ram and an included ssd, have support for dual 4K monitors and so on. No WiFi out of the box, but they do have a second m.2 that can be used with a cheap WiFi card if that is what you need (or you could install a second ssd).