Banana Republic has an extra stacking 40% plus 20% discount on sale items. Discount will show up on cart.
For gap family members, extra 10% off with code :BRCARD
Shipping is free with $50 purchase. Luxe cardholders get free shipping no minimum with code :LUXE
This dress is $20 after 40%+20% coupon and available in all petite sizes as of this post.