SheIn offers its SheIn Women's Spaghetti Strap Color Block Dress in Pink/White for $14.59. Coupon code "inst33" cuts it to $12.05. With free shipping, that's $6 off list and the lowest total price we could find. It's available in sizes S to L.
Note: Uncheck "Add Shipping Insurance to your order" during checkout to remove the 99 cent fee. This item ships from mainland China and should arrive in three to four weeks.