Every time I'm in Vegas I get my tall slushy drink there. Located in the Miracle Mile of shops by Planet Hollywood -tucked in the back, Dear Yelper.
The MOST REASONABLY PRICED drink you will find. You will see others more conveniently located but it is worth going out of your way for this place.
Some patrons keep their containers and bring them back to Vegas when they revisit in order to get the reduced price refill. Although it's not worth the hassle for me, that option is available to all.