You'll probably find that it works. My even older Elsa Synergy II (16 MB, TNT2-based) works, but it's slow for anything above 1024 x 768 resolution and more than a couple of windows.
Elsa did good stuff, but their CAD tweaks and utilities were for AutoCAD. They suffered bankruptcy a while ago, and the German firm that bought Elsa's designs no longer seems to maintain
If I were starting out with a modern computer, I'd look for a newer card from a maker still alive and kicking.
As for what to pay on ebay... simply search on the card in question, then search "completed items." You'll see a range of prices for completed auctions.
Dave G.