In an effort to minimize the change that ends up in my pocket, I'll give partial payment in coins. For example, if the total is $xx.27. I'll give the two pennies, expecting three quarters in the change. Some cash registers will deal with this, some won't. Some clerks can deal with this, some will pause, others are totally flummoxed. Some will look from hand to hand, hand to register, back at me, several times, then decide that I'm totally out of it, make some sort of comment about twenty seven cents, ultimately giving back the two pennies.