The initial idioms of the letter A

a mixed picture	a modest proposal
a Monday morning quarterback	Monday morning quarterback
money-spinner	a money-spinner
monkey off (one's) back	a monkey on back
a monkey on (one's) back	monkey's allowance
a month of Sundays	monthly meeting
moonlight flit	mop head
moral low ground	a morning person
mote in the eye	a mother hen
mother lode	a mother lode of
a motor mouth	a mountain to climb
a mouth	a mouth full of South
a mouth to feed	mouthful of marbles
a movable feast	muffin top
a mug's game	a must