CVS boasts a wide selection of Korean Beauty products. They're seldom discounted on their own; however, they are currently eligible for 30% off and free shipping via coupon code "30FREESHIP". This is an excellent way to save on K-Beauty items from a trusted retailer while avoiding long waits for shipping from overseas merchants. Deal ends March 10. A couple of best bets, each with free shipping:

Peach Slices Hydrate Sheetmask for $1.74 ($1 off and by far the best shipped price out there)

Holika Holika Aloe 99% Facial Cleansing Foam for $4.54 (a gentle savings of $2)