Aeropostale offers its Aeropostale Women's Solid Open Knit V-Neck Sweater in Salmon, Grey, and Cream for $10. Coupon code "FACTORY30" drops it to $7. With $7 for shipping, that's $43 off list and the lowest total price we could find. It's available in sizes XS to XXL, although not in all size/color combinations.
Orders placed by December 21 are guaranteed to arrive by Christmas.