American Eagle offers its American Eagle Women's Classic Peacoat in Navy for the in-cart price of $53.99. Coupon code "36892051" drops it to $43.19. Even with $7 for shipping, that's $77 off and the lowest total price we could find. Sales tax is added where applicable. It's available in sizes XXS to XL.
Update: It has since dropped to $33.59 after the coupon.