These things are inexpensive to begin.
In a non-working condition, I'd be surprised if you get more then $50-$100 for it.
Then you got to figure shipping and hassle of negative reviews or someone trying to open a claim against you.
If you had some tooling included with it, that might be worth more than the HF mill, but it sounds like you're keeping it for use with new machine.
If it was me, I would put it on local CL and see if you get any bites at $150, knowing whoever shows up will try to get it for less.
Otherwise, keep it and play with spare parts.