In this age of mirrorless lens appropriation, 200 euros is bargain basement for any f1.2 lens. I'd smell a rat or naivety. Make sure the lens is all it claims.
$200 is a good price. A nice one on ebay will fetch $400-600 sometimes. I have one, it's an interesting lens to say the least. It has very unique bokeh, which is probably it's most defining characteristic, and it's unlike any other OM lens in that regard (even the OM 50/1.2 is significantly different that way).