Well, first of all, I want to thank you for obtaining and offering a piece of vintage tech for sale. Some of this sort of stuff IS getting a little hard to come by.
Please understand that the word "rare" is very overused on eBay and some other places. Enough so that the word has become almost meaningless to those that frequent eBay. Additionally, when listed in a place or specific category for vintage gear, the word is often redundant.
When I look at that item, all I see is a rather generic VGA/EGA combo card. Most VGA cards that have EGA were rather early in the life of VGA, and likely do not support extended VGA resolutions, and are usually not very fast. These come up quite commonly on eBay. This specific model? Perhaps not, but OEM manufacturers made many variants, although I would assume they all do roughly the same thing.
If I were interested in this card (which, sorry, I am not), I would want to know more technical details about this specific model, such as supported resolutions, total memory, if it could handle RGB monitors, does it work on an 8088 (an 8-bit ISA connector does not guarantee that) that sort of thing. What would this card do for me that others do not?
For a video card, ideally one should list both the brand and the chipset. Buyers might search for one or the other. Annoyingly the brand or card model is often not written on expansion cards. The brand can sometimes be important for finding correct driver software or utilities.
I'm hesitant to comment on the price, since I don't really know the euro, or what the market is like in your area. It sounds like you might have a very good reputation elsewhere, where people may be happy to pay more for your service. But with only 3 posts, that is not true of this site. Please understand that there have been some issues with scammers recently.
Of course, the entire "tested, no video" strongly suggests that it may not actually work, or not work properly in other systems. That would normally badly hurt any sale price. Although, selling "as-is" seems to be almost a requirement these days.
I can't really tell if there is damage or removed components. To me it looks like the vias may just not have been filled in. A higher resolution photo might clear that up. Note that this forum can store JPGs up to 250k Size it with a photo editor first, otherwise the forum may automatically shrink the image.
Just glancing at eBay I see a 16-bit EGA/VGA card listed for $59.99+SH, and a couple others that are just a bit more. Looking at actual sales, another 16-bit EGA/VGA sold at bid for $8.50+$10SH, and another for $20+$8SH. It seems like most sell for about $20-$40. I do see an 8-bit model that sold for $50. You have lots of competition. So, if I wanted something like that I would just wait for a better deal to come along.
Also, if it is not obvious by now, be aware that this forum is filled with critics, cheapskates, and people who browse eBay more than they should.
Expect to get comments and criticism.