It seems to have *just* changed. I put in an order and in my cart and receipt it says $11.49. Went to double dip and when I added to cart it now says $18. YMMV but you might be able to have customer service help out since the listing still says $11.
EDIT: the listing changed along with the Retro MLs that were on sale, now they're 20% instead of 50%. rip