There are various games on discount at the moment on the PSN store. Especially for the PS4 games that if you haven’t picked up when they first came out are very good choices in deed.
SOMA, a survival-horror game developed by Frictional Games and that debuted back in 2015. The second game is Batman: Arkham Knight, which debuted the same year, but via Rocksteady Studios. The third game is The Wolf Among Us, which hit a year earlier in 2014 via Telltale Games. And the fourth and final game is Double Fine’s Psychonauts, one of the best games on PS2 and a game that just got a sequel itself. (Source)