Price can vary significantly from under $200 for an Intel N150-based system all the way up to Ryzen AI Max+ 395 systems costing $2000.
A lot of the mini PC makers have gotten pretty legitimate recent years, and some makers like Minisform can even charge a bit of a premium based on their brand name. More "traditional" hardware makers like Asus and ASRock also sell Mini PCs. And of course Apple is also a significant player in the Mini PC world with the Mac Mini. So definitely not just an Ali express thing - although Mini PCs can certainly be purchased there as well.
These refurbished 1L "tiny" desktops from big vendors like Lenovo, HP, and Dell are also popular with the Mini PC server crowd. https://a.co/d/g1mgUnl
It looks nice, though. I'm impressed they were able to get 11W idle power consumption with a 400W power supply (most mini pcs have much smaller power supplies, which are supposed to be more efficient with smaller loads). [1]
[1] https://www.jeffgeerling.com/blog/2025/i-clustered-four-fram...