So last week I had to take the public bus to my house, and I didn't have exact change for 1.25, so I gave them a 5 from lunch money, and the dude says "I'm not giving you change, I've got a schedule to keep."
So, my response is to pay with pennies from now on.
I think that will be hilarious... Make sure when you go to give the pennies to the guy just dump them all over him and be like oops, then throw the bag at him and sit on the bus.