A 24/7 liquor store in Vegas is not hard to find so I was fortunate when the directions my uncle gave me and my bro to his preferred liquor store fell flat that X.O. Mini-Mart was in the vicinity.
It's the perfect mini-mart: lots of snacks, drink mixers, beer, and a wall of liquor to choose from. We were left with vague instructions on which tequila to procure ("just bring back something with 100% agave") and thanks to the helpful and kind gentleman behind the counter, these two white kids were able to bring home some decent tequila that met said vague criteria and didn't break the bank. Good service goes a long way, y'all!
Related: the parking lot has a great view of the Stratosphere against the sunset, too.