Marc Jacobs is offering 2 nail polishes for $18 with code MJNAILS, ends 9/25. The regular price is $18 each. Plus, shipping is free.
You may also get this offer at Marc Jacobs Beauty with code MJBNAIL, but you have to meet $50 to get free shipping. You can use code MJBNAIL on the $24 limited edition enamored hi-shine nail lacquer too. The price will come down to $18 for two.