Recently Sixbids put most of their search database behind a paywall. Only the last year of auction results can be viewed for free. I loved using their search because it had most major auction houses, some even back from the year 2000. But most importantly, you can also see the prices for free (but now only from the last year).
Now the free version is just like CoinArchives (last 6 months and prices) or NumisBids (last year and prices).
The fourth one I now mostly use is acsearch. They still have their complete database from the digital age for free, but you have to pay to see the prices. Also, they don't show pictures from Künker, Lanz München, and probably some more, for to me unexplainable reasons.
EDIT: The pictures mentioned above seem to just not show in Germany. With a VPN I can see them again. No idea why.
Now as a consumer, it's way more tedious to find out the market prices of rarer coins that don't show up in every auction.
What sites do you use? Is there some site I'm missing? And what do you think about the current state?