Thanks guys! A correction: the shipping cost was more than expected so now I paid slightly more than $50. But the coin by itself was less that.
This is why we collect ancient coins - because the time and effort we put into learning about them still pays tremendous dividends. The coin isn't in a piece of plastic that tells you what it is, and even if it were, there is no simple price list we can pull out to quote the exact market value. You won this coin by your own knowledge and experience. Be proud.
I thought it made more sense to resurrect this thread than to start a new one. Here's an example I was able to pick up recently, worn but a clear revaluation. It appears to be the same host coin as Ardatirion's example.
I always wanted one of these but really want a sestertius with LXXXIII cut. https://www.acsearch.info/search.html?id=2980140
A very interesting coin and congratulation on finding it! Countermarked or revalued ancient coins have, in a way, special appeal because they often relate to specific events in history. I felt the same way when I found an as of Nero with a Vespasian c/m in my collection (it was countermarked in 69 by Vespasian's supporters during the events of 68-69). By analogy, I find the association of your coin to the Vandals in north africa particularly interesting. Great find!