Pricing on ebay can get crazy sometimes, but I see one for $25. I have one I got for free many years ago, and another I paid $20 for with a box of misc. hardware from a garage sale. The mini G4 may be sought after because it is the highest
performance prior to the maybe somewhat finicky G5 series. Don't get me wrong, I'd love to have a G5, but maintaining liquid cooling would not be fun for me. I like the
small footprint (size) compared to the G5s or
Talos. Sought after
Open Firmware may be a reason, but Power11 — with open firmware as nice as that would be, it is too bulky and pricey for me. I am cheap, and quite satisfied with what I already have.