A best bet is the Alloy Women's Belted Drama Coat in Ivory (pictured) or Black for $69.99 before the above coupon and $49.99 after. With $8.50 for shipping, that's $80 off list and the lowest total price we could find. It's available in sizes S to XL.
Of note, Alloy also offers free shipping sitewide via coupon code "FEBFS". Update: Meanwhile, coupon code "ARB2" takes 20% off sitewide, which may yield better savings for purchases above $100. Note that you can only use one coupon at a time.