Signed up and got my first movie today. Apparently you can exchange it in store for a movie to rent for free or certain movie and non-new game rentals at a discounted price. So I'll be going to my "somewhat local but not as local as the two other locations they closed" Blockbuster to see if it'll work.
And apparently the in store discounted rentals don't count towards you queue or discs out, but you have to return them in store and before a due date. I'll see soon enough hopefully.
Edit: I read this info here:
https://www.blockbuster.com/signup/howItWorks
DOUBLE EDIT:
On the change plans page under the account settings it says this:
Since the next billing date is in January does this mean you could upgrade to a three disc plan for the trial with no fee until the end? The obvious answer is NO to me, but I think someone who isn't me should test it.