I have learned the hard way with my friends and good tequila. I have poker night about once a month with anywhere from 8 to 20 guys. I was going through $200+ a night in just tequila. I finally figured out that I could start out with like a DJ anejo and as the night went on, the more some of the guys would get a bit drunk, I could switch them over to a plactic jug of Aztec Gold tequila and they never new the difference. In Fact. I was telling them it was Rey Sol and they were telling me it was the best they have ever had.
The worst though, was when I poured a friend a shot of Porfidio Barrique in a snifter and he tossed it back like a cheap whiskey....I just about died. :P