Nier: Automata has already sold over one million units, which is a big achievement for what is a rather niche game. As a result of the success, Square Enix has begun reprinting the original Nier for PlayStation 3.
Reddit user lupianwolf spotted the pre-order for the game on the official Square Enix store. Price of second hand copies has been going up since the release of Nier: Automata as a result of the increased interest.
Nier was originally released in 2010 for PS3 and Xbox 360. And its origins are that of a spin-off to the Drakengard series. If you haven't tried Nier: Automata yet, there is a demo available on PlayStation Store.