so this neutron walks into the local convenience store and grabs 3 cans of beer and says to the girl at the counter; “So how much do I owe you?” The girl smiles: *“For you, no charge”
...adapted from a joke online... NOTE from wiktionary: NEUTRON (physics) A subatomic particle forming part of the nucleus of an atom and having no charge; it is a combination of an up quark and two down quarks