Can you buy GOW:ascension online pass separately?

I bought a used copy because I didnt know you need a freakin online pass to play online. Can you buy it separately? 

where and how? cant seem to find it in psn

Go here:

https://store.sonyentertainmentnetwork.com/#!/en-au/games/god-of-war-ascension-network-pass/cid=EP9000-BCES01741_00-ONLINEPASS00000R

If that link doesn't work for you (and it probably won't if you're not in AU), just go to:

https://store.sonyentertainmentnetwork.com

Sign in, then use the search bar to look for 'God of war ascension network pass'.

Alternatively, return the game where you got it, and get a new copy from somewhere else. They are fairly cheap now anyway. The back of the box should tell you if it requires/includes a network pass, which is something to look for when you buy used games.

It's $20 New on Amazon, for example. Here.