Care for your Bush-bashing in daily doses?

Ahhhh… nothing starts the day like a randomly priced cup of coffee. You see, every morning I’m in the office I pop down to the snack bar two floors below and fill my monster mug with hot coffee. So far, pretty typical, eh? Then I go to the cashier (it’s always one of the same two girls) and I pay. But what I pay seems to range freely from 70 to 90 cents. I paid 86 cents this morning. I’ve paid 70, 75, 81, 86, 90, and maybe a few others I’ve since forgotten.

So being scientifically minded, I’m trying to determine whether this is truly random or whether there are other factors. The mug is the same, the product is the same, the cashiers are the same. I’ve ruled out time of day and day of week which I think covers all the obvious stuff. I’m down to looking at whether I pay more when I’m wearing green shirts, or get a discount if I say “hi”.

Maybe they should run a lottery. If I can correctly guess what they would have charged me, then it’s free. I’m also wondering what would happen if I asked the first cashier to wait and went to the second to see if I could get a better price. Or maybe I should just go back to bringing my Thermos.