Rival Schools
In recent years, Capcom has been pretty aggressive about issuing HD re-releases of it's prior fighting game IP. The first instance of Capcom doing this was of course Super Street Fighter 2 HD Remix, which was released to XBL and PSN in late 2008. We've previously discussed Marvel vs Capcom 2, which was given a PSN/XBL re-release in 2009. In 2011, Street Fighter III: Third Strike Online Edition was released. And in 2013, Capcom released HD versions of its Darkstalkers games bundled together as Darkstalkers Resurrection.
These re-releases have generally been very warmly received critically, even if they have suffered from lukewarm sales numbers. Darkstalkers Resurrection in particular suffered from poor sales, according to Capcom.
One series was left behind by Capcom during its re-release era. Rival Schools and Project Justice, both very popular among retro fighter fans, received no HD treatment. Apparently Capcom has licensing issues with the games which all but guarantee that the games will not be released.
As a result, if you want to play either game legally, your only option is to go back and buy the original games and play them on the original hardware. These games have therefore been immune to some of the depressed prices seen by some of these Capcom fighters after the games were given the re-release treatment.
Rival Schools is not especially rare. I count 23 CIB and 2 sealed eBay listings at the time I am writing this. But for a PS1 game, that's not a huge amount. And a search of the sold copies on eBay shows that the game does sell briskly, with CIB copies fetching up to $60 pretty regularly. A sealed copy sold for $179.95 on May 6th.
It is a fun game in a beloved series. And since we know it is very unlikely to be given a re-release, it might be worth picking it up now at these price levels.