AMD FX-4130 CPU
Radeon HD 7770 Ghz Edition GPU
4 Gigs of Ram
320GB 7200 RPM HD
A not-ugly case (unlike most budget cases).
ASUS M5A78-LX Plus motherboard.
Corsair CX-430.
This computer can run Blockland on medium to max settings, depending on brickcount. For the most part, I run high to max at a playable 40-45 fps. Keep in mind I'm running Linux, so Blockland isn't even running native.
All this for just ~$310... With maybe $400, you could get a much better computer.
Also guys, don't just tell him to spend more money. I had this same issue in the computer thread when I needed help, it's quite unhelpful to just tell him to spend more many that he probably doesn't have, it's also very annoying. Instead, give him the best build he can get for the money. And I know he can't nessesarily get a good one, just give him the best he can get.