Not 100% sure what you mean Paul. If your just wanting to get it for PS4 you can buy it through the web site K.wong linked, it's the official PlayStation Store. Just log into your SEN account and buy it. If you mean buy the PS3 version and play it on PS4 you can't, PS4 is not backwards compatible. (get to work on that Sony)

Also this might be a Black Friday sale, not 100% sure if it is since Sony hasn't posted the list yet. If it is Black Friday we are putting all Black Friday deals in the Black Friday thread.