Playstation Plus purchase online?

So I've heard Jeff on the podcast talk about how he just goes online to purchase all his ps plus games. I would love to know how to do this. I went to the PlayStation website and couldn't figure out how to do so.

https://store.sonyentertainmentnetwork.com/#!/en-ca/free-games/cid=STORE-MSF77008-PSPLUSFREEGAMES