Mailing them is not a issue, getting raped by Customs is.I'm in Aus, I would check out their postage costs to your location. I purchased 3x 16TB Exos X18 drives at US$199 each (they are out of stock now), was $93 for shipping. Even with Amex taking a cut on the exchange rate it came out to ~AUD$1100, which for 48TB of raw space is soooo much cheaper than anything I can find in Aus.
That is AUD$22.90/TB vs the best I can find on any retailer in AU being a drive that I have to shuck and therefore loose warranty on.
The packing on these HDD's was amazing too. Came in a box designed for 5 drives, closed cell foam around each drive and then double boxed with bublewrap around the inside box.
That and $200 for a HDD, meh. If I actually was running out of space I would have gotten some and have them shipped to my contact in the USA.