GearXS offers the Hanes Women's Hi-Cut Panties 14-Pack in White for $19.99. Coupon code "GXS-30" cuts it to $13.99. With free shipping, that's $1 per pair and $18 under the lowest total price we could find for a 12-pack elsewhere. They're available in sizes 6 to 10.
Update: Coupon code added above.