$70 on my QFR, including the paint job. The PBT set was a Christmas present.
$100 total on my RK9000"ECE" (Ergo Clear Edition). That includes the keyboard, paint and painting supplies, switches, stickers, springs, and Teflon Silicone lube (need to desolder and relube it with Krytox).
~$80-90 on my GH60 for the caps, case, switches, springs, and PCB.
Way too much on my experiments with metal casting, resin casting, USB cables, and key cap pullers. Maybe one day those will result in some good community knowledge and me breaking even or even turning a small profit.