H&M offers its H&M Women's Lace Dress in Cerise or Black for $10 plus $5.95 for shipping. That's $15 off and the lowest total price we could find. It's available in sizes XS to L, although not in all size/color combinations.
Nordstrom offers the Like Mynded Women's Mesh Inset Body-Con Dress in Cobalt for $23.98 with free shipping. That's $24 off list and tied with last week's mention as the lowest total price we could find. It's available in sizes M and L.