SheIn offers its SheIn Women's V-Neck Sleeveless Bodycon Dress in Black or Red for $12. Coupon code "INST33" drops it to $11.28. (Be sure to uncheck the shipping insurance box; otherwise, it adds 99 cents.) With free shipping, that's tied with last week's mention, $6 off list, and the lowest total price we could find. It's available in sizes S to XXL.
Note: It ships from mainland China and should arrive in three to four weeks.