The monthly subscriber item used to be handed out automatically to whoever had an active subscription (moving back to legacy soon!!) when it went live. It was fickle. It missed people often enough that I was granting the item by hand a few times a month to anyone who wrote in, which is not a system so much as me being the system.
So it works differently now. On the day your subscription renews, you get 1 Subscription Point, and you spend it yourself.
Take it to the Subscription Shop. Every item in there costs exactly one point, including the month's new item. Points don't expire and nothing ever leaves the shop, so if this month's item isn't for you, hold the point until something you want shows up. Quester, Councilor, and Goddess all earn a point per renewal. Keeper does not.
The Weekend Bonus Items shop has closed and its 140 items moved into the same catalog. That brings the shop to 210 items, the oldest of which went out in July 2013.
Every item also has a 500 CSC price next to the point price. Cash Shop sales apply to it. This is mostly so the older items keep circulating: a lot of them have been effectively out of print for years.
If you were subscribed when this went in, you've already been given points for it. Check your balance at the top of the shop before you buy anything.