amadeus777999 wrote:What would such a chip cost... 200$?
It would depending on the bidder and how well advertised the auction was. Recently, people were willing to pay north of $500 for a Cyrix 5x86-133/4x. Comparing the rarity of the two chips, the K5-200PR was less rare, so I suspect it would fetch in the $150-$300 range. For someone just trying to offload the chip to other collectors on CPU-World, perhaps it would fetch $70.
As of a year ago, I could still remember where I sourced mine and for how much, but now it escapes me. What is happening to my memory? Oh... 3 screaming kids and little sleep can greatly accelerate the aging process.
Trying really hard to recall, I think I paid $65 USD for mine many years back, from a collector retiring from the hobby.
Plan your life wisely, you'll be dead before you know it.