Cavihour @ Red Square (Las Vegas)
When we were there IIRC the deal was that you had to get two (or was it three?) cocktails made with one of the more expensive vodkas, and you got the (least expensive) American 'caviar'. Sorry I can't remember the details, but we looked at it and decided it wasn't worth it $ wise. Got some excellent vodka flights instead.
I go every time I am in LV. However, it is a free $65 order of American caviar when one person buys two drinks made with Imperial vodka. The drinks must be pure vodka or a martini. In months past if two people each bough a drink you get the caviar. Now one person must buy two drinks for the freebie. So, my wife has a drink and I must order two for the freebie. The drink made with Imperial vodka are expensive--something like $15 per drink.
Not as much of a bargain as you hoped for but it is still fun. And the bar is great even if you pass on the "free" caviar.