The Show Me State is showing how the global oil glut is padding American pockets. Thanks to low gas taxes, Missouri is the first state in the nation to boast average pump prices below two bucks a gallon for the first time in five years. Oklahoma will follow suit within days. The national average gas price has sunk for 92 days straight and now stands at $2.32 per gallon, the lowest since May 2009. Cheap gas is already shifting consumer behavior, from auto purchases to driving habits.