Shipping can be strange sometimes.
When I was active I shipped internationally and didn't have any problems. But all the stuff that went international was cheap. I did have a buyer in Germany ask how much the partial Victrola would cost to ship. (About 50Lbs packed, actually an upright machine that someone cut the useful part off of. Ugly but worked great)
For small stuff like one card or some small bike parts I had a flat price that was just above postage, at the time around $2. International at cost. What got weird was that for a very light package Shipping to Canada and most of western Europe was actually around 1.50. So the international buyers got a pretty good deal.
I figured packing materials as an expense. I reused a lot, and got a huge batch of bubble mailers for CDs from a friend who bought a vanload of shipping supplies from someone who quit Ebay selling.
One of the parts I had a lot of I was selling for $15 a set. And sold around 10 sets a week. Ebay started pushing free shipping, so I figured I'd give it a try - they might have offered some deal like no insertion fee. So I made it $20 with no shipping. And sales nearly doubled
Since I did stamps and general antiques and odd stuff, I got some interesting requests. A guy from Japan who collected postage meter envelopes asked me to ship his stuff by surface mail which was being cancelled at the end of the month. The poor guy at the post office tried for about 15 minutes but the system wouldn't allow a letter to got surface. (They were ok with trying since I usually had everything entirely ready to go, and knew the rules about what I could send with what service)
Fun stuff, I kinda miss it. I don't miss the LCD buyers they really tried to attract. "Shipping is $2, international at cost"
"How much to ship to Kansas"
Steve B