Battlefield 4's been on sale for some stupidly low prices on the PlayStation Store lately, and if you want to really take advantage of the title's deep discounts, then you'll probably want to nab all of its DLC for free. EA has made all five (!) of the outing's expansions complimentary on the PlayStation 4 and PlayStation 3, and we can confirm that this isn't a con as we've been playing them ourselves.
To take advantage of the offer, you'll need to "purchase" the content before 19th September, so get moving. It's perhaps worth noting that you can "claim" the add-ons even if you don't own the game, so maybe chuck them in your basket anyway in case you ever end up with a copy of the first-person shooter in the future.