Online multiplayer free it's not like Xbox where you have to buy Xbox live to play online?
Also I don't know if this is right thread to ask this question.
Do I have to pay to play online with PS4? Yes. To game online on most games, you will need to buy a PlayStation Plus subscription ($50 a year). Social features like having PSN friends, streaming services like Netflix and most Free-to-Play games like PlanetSide 2 will not require you to pay for PS+ however.
Credit: http://www.playstationlifestyle.net/2013/06/17/the-ultimate-playstation-4-guide-paid-ps-online-hardware-games-news-and-more/
- Sam