Missha US is also having a 40% off sale. Everything is 40% off site wide, and they have a gift with purchase. Spend $100, and you become a VIP member. VIP members get free shipping on orders over $20, 30% off all regular priced items, and a birthday reward. If you don't qualify for free shipping, ground shipping is about $6.
Amazon also carries a lot of Missha items. I feel like they are the cheapest, especially if you figure in shipping. Here is an example:
M Perfect Cover BB Cream #13
Amazon : $10.80 Free Shipping with Prime
Missha US : $13.20 Free shipping with VIP or $5.99 Ground shipping.
Soko Glam : $13.20 Free shipping on orders over $35 or Shipping is $6.95. (Coupon code: MISSHA4U is needed to get 40% off).