Sheinside offers its Sheinside Women's Spaghetti Strap Sheath Dress in Red for $8.99 with free shipping. (Uncheck "Add Shipping Insurance to your order" during checkout to remove the 99 cent shipping fee.) That's tied with last week's mention, $5 off, and the lowest total price we could find. It's available in sizes S to L.
Note that this item ships from mainland China and should arrive in three to four weeks.