The only place I've found locally that sells a big bag of white millet (not the mix, which has those big red seeds that NO bird wants) is Southern States.
I'm chuckling, imagining Susan setting out with great purposeful strides to get the millet that "her" juncos must have at once! :-)
I've skidded into the garage at the start of a snowstorm with 50 pounds of BOS in the back of the car, so I understand.