usually they don't care about the penny...
It's called Take a penny leave a penny
That's happened to me before, so I gave the guy $6 and he just gave me a dollar back cuz he didn't want to count out 99 cents.
heheeheee I do the same thing Every time it happens. as soon as I find out I'm gonna be short by just a little bit of change, I put on my best "shocked" look and go, "ahhh man! I'm short by like a few cents! now I can't get it..." then look around.
I always get the money. o_o