When we went in July, we bought the animal topper cup and it also had a sticker. Just like the previous poster said, it was only good for that day. Wish I had know about that earlier in the day since we bought ours at about 3pm and left at 4pm.
We also bought a cup at Blizzard Beach and it was a life-saver.
FYI - not WDW related, but they also have the refillable cups at Seaworld.