Liquor Library is cheaper than hotel gift shops, but also more expensive than CVS/Walgreens. I'd say it depends on where you're staying; if you're going to, say, Aria or Monte Carlo, there's a CVS right outside that you can stock up at. If you're at Mandalay Bay, it's much more of a hike to get anywhere inexpensive.

 

I was looking at your picture to see if they carry the marshmallow or whipped cream flavored vodka. One of my favorite drinks is using that vodka mixing it with Simply Limeade and adding a maraschino cherry! So good and refreshing in the summer. It's called a Key Lime Pie.

 

They had a pretty good selection. I would bet they have one or the other there.