My current strategy for how much total I'll pay for a coffee is FlOOR(price+.50) + 1, which keeps the bill nice and clean and kicks some goodwill towards someone who makes less than 1/5th the average earnings of my coworkers.
I'm going to charge you $1.50, then.
> kicks some goodwill towards someone who makes less than 1/5th the average earnings of my coworkers.
The coffee shop owners? They're probably making a decent amount of money no?
I make my own coffee. It's not hard.