At the Tokyo Game Show (TGS) yesterday, Capcom Producer Yoshinori Ono announced that the upcoming fantasy role playing game, Deep Down, will be a free-to-play title when it gets released for the PlayStation 4. A PlayStation Plus subscription may be required.
Capcom is looking at having an open beta available for players of the online game sometime around the launch of the PlayStation 4 in Japan, which is slated for February 22nd, 2014.
As far as a PlayStation Plus subscription, Sony is leaving it up the the publishers of any free-to-play online multiplayer games as to whether it will be required or not.
Here's the Deep Down trailer from TGS ...