I couldn't believe my eyes, when I just checked current Humble Bundle offers and saw this Neo Geo special there:
https://www.humblebundle.com/neo-geo-encore
Of course, these are just ports to other platforms (even browsers as it seems), so no "real deal". There are also soundtracks.
But needing to pay just $10 for all of them and giving some of that to charities doesn't sound too bad I think.