I have a lithograph hand signed by Antoine Sereels It is 1 out of 275. How much is this worth now?

I recently bought a painting by his hand for 33 €, another went 95 € the same day. On other auctions I saw them go as high as 300 €. I'd say a lithograph in good condition would be worth around 50 € at least, seen it's age. Also, there is not that many of his work around it seems. Even though the litho is one of 275, it doesn't mean the other 274 are still around and in good condition ;) Price also depends on topic of course. Hope that helped, even if your question is a few years old already :)