The buyer always pays for shipping, here's how it works:

Prepaid Parcel Shipping - The buyer selects their preferred carrier & service level and makes a single payment for hops + shipping during checkout. The shipping label is purchased during checkout, then provided to the seller (or their merchant if dropshipping contracted hops). 

Freight - Orders that are too large to ship economically via parcel, ship via Less Than Truckload (LTL) service and may involve a freight broker who will collect payment (often in advance) from the buyer. See How to Ship LTL for details.