Are they scrap? Do you care if they bang around? If not, stack and tape them together, wrap them in cardboard, and send them in a prepaid USPS box. Like they said, up to 70#'s. If you have a FedEx account, they are very reasonable, particularly if you are sending business to business. You might also try media mail... I don't know if it would qualify, but if the price differential was great enough, I would say that the hard drives were full of media that needed to be shipped were I to be asked.