I have a Compak K8 that I did some custom work to.
Powder coated the case in Padmount Green and the doser in Matte Black
It would sell with an Orphan Espresso single dose hopper, as well as a DIY Mazzer style funnel.
It has all original parts with exception to the tamper that mounts to the doser.

All works as it should, I just want to stick to single dose grinder

I'm trying to determine a fair asking price.

Any help is appreciated!

See How to price used espresso equipment and How to choose an espresso machine and grinder at the "right" price (specifically "What are your recommendations for selling/buying used espresso equipment?").