In EU it was around 5 euros if you had plus a couple of months ago. I got it for that price and it was worth it.
For psplus I think that a part of the 50 euros you pay go to publishers who allow their games to be offered in plus and the rest is just profit. I also think that they have a deal on every game since a game like Battlefield will benefit on a different way than a PSN game.
Battlefield will get more crowded servers, you can buy DLC (on discount) and EA also benefits for awareness for the next installment of the Battlefield franchise. However a small developper can actually become popular and receive recognition from the new community which will help for their older/newer games that they'll release.
Stories unfolded with my home made rap songs. Feel free to listen here with lyrics: https://youtu.be/vyT9PbK5_T0
