Never bet on a coin flipped by mathematician and magician Persi Diaconis who can flip it so that it lands on heads at will. Diaconis has also shown, using high-speed slow motion cameras and plenty of physics, that when flipped by a regular person there is a 1-2 percent bias in favor of the side that begins up. Some more info here.
Over your lifetime this information ought be be worth quite a bit to you. Remember where you heard it first and act accordingly!