It is not free, unfortunately.
I was set on a ryzen 5 3600/3600x, but happened to come across the used (for about a year, never over clocked according to owner) 9600k. I’m just wondering what a fair price for that would be. I’m not paying anywhere near retail price for it. If $150 is a fair price, I’d probably pass. If $100-125 is more of a fair price, I’d consider it. If sub $100 is fair and I can get it at that price, I’d probably do it.
The 9600k is still a very usable CPU (heck, I still find my i5-3470 perfectly usable for 90+% of what I do on a regular basis), I doubt you'll find many willing to get rid of a perfectly working one for less than $150.