Practically speaking, in 2026, are there any big ticket items an American could buy abroad and have the travel economics work out to their favor?
The big one I do is medical tourism, though I have family in Taiwan. I've done a bit of dental works where the cost in the US is $3k-$5k after insurance, and at Taiwan is maybe $300-$500 (10x diff) cash pay. I've also done scan-all-the-things health spas in a Taiwan hospital for $300-$500, where American equivalents are again 10x.
I remember decades ago hearing stories of motorcycle racers going to japan to get a honda RS125, put it in their luggage and bringing it back to the US.
They are small race-only 2-stroke motorcycles, not sold in the US at all.
Inside the European Union, traveling to other places to buy things from there would only seldom be profitable, when considering the travel expenses.
On the other hand, I frequently buy things from online shops located in many of the EU countries, because very often for various kinds of things that I want to buy I find the best deals in different countries. There are no extra expenses but shipping, so it is frequent to order things from far away, because at a local shop near me they would be more expensive than buying from another country, even with the added shipping.
Japanese stationary - and I am not kidding.
Weirdly for me: IKEA. I’m within ~240 miles of an IKEA in Canada and an IKEA in the US.
While they’ve started to inflate some items to meet currency conversion rates, some items are still cheaper for me to purchase in Canada directly and bring back to the US.
For instance, even at small scale: one BILLY bookcase, article number 205.220.46, is $90 CAD (~$65.70 US) at IKEA CA and $79 USD at IKEA US.
YMMV coming back across the border but in my experience I just got waived through the border every time I told them I was “just coming back with some cheap crap from IKEA”.
Labor-intensive products. Custom suits, leather jackets, etc., are so, so much cheaper in places with lower costs of living. For individual items, flights might make it a toss-up, but on the scale of an entire wardrobe, flying to Turkey, having a bunch of tailored clothes made up, and then flying home would definitely work out.