Fat Tuesday
Restaurant @ Stratosphere Casino Hotel and Tower
Since Casino Royale doesn't do the cheap Margaritas anymore, Fat Tuesday is your best bet. You actually have to ask for the cheap version ($1.50? don't quote me) but our party went for the $10 cocktail glass Margarita which I found a bit expensive. They have different sorts, the RED BULL INFUSED MARGARITA wasn't too strong but you could feel both the Red Bull and the Margarita after finishing it. A bit pricey after all and I wouldn't go out of my way to get that frozen booze again. Only when passing by.