Is there a way to do this? Like pay for it, get a CD key you link to a friend or something. I couldn't find anything on this subject. I think it would be a win/win for both players and Sony.
They used to do it years ago in their store site section, now you have to do it via Steam Gifting (if you both have it and expansion is on there, I'm not sure how late they put it on Steam though).