That's certainly an interesting area you've chosen to collect there, Noxx. Transylvania,
Vlad III the Impaler (the historical Dracula) and all that...
Unfortunately, the time period falls "in the gap" as far as my reference books are concerned. The only book I have which covers the period (Coins of Medieval Europe, by Grierson) has only this very brief statement on 15th century Romania: "In the Eastern Balkans, the principalities of Wallachia and Moldavia continued to mint small silver or billon coins, as in the preceding century". There's a bit of general information on this
Wikipedia page on Romanian coins.
As I understand it, coins of this time and place are hard to come by in legible condition. And of course, Vlad III's coins are highly sought after, which drives the price up.
To close with a nitpicky point: technically, they're not really "ancient" - that word is reserved for really,
really old coins - normally pre-500 AD. The period 500 to 1500 AD is normally called "mediaeval" (also spelled "medieval")
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis