Yes, although we didn't personally do it, a women seated next to us at Boma bought them for her daughters without buying the drink. I don't know how much they were though!
You can also order the cup w/ the straw and the light up attachment w/ another kind of drink (for the same price).
We did this in December since they use the Minute Maid Lite Lemonade to make the Pirate Punch and we can't have artificial sweeteners. Our waitress told us we could get the kids milk in the cups instead...no problem.