>>6736691Marking down means they'll put the price on the box lower than what it actually is so you don't get hit with customs fees and the like. When you're confirming the shipping and paying for the stuff there should be a box to put comments about the order in, and I tend to just ask them to mark the price for the parcel down.
I last ordered a MG Rick Dom, 2 HG GMs and a pair of God Hands and they marked all that down to like 1500yen or so and it flew past customs with no issues.