Within the EU at least, "sin taxes" work well for this because carrying them across the border for personal consumption is the only legal workaround. For most other things, if they're notably cheaper in another EU country, I can just order it from that EU country.

For example, I'm in Ireland (relatively HCOL), and I regularly visit Slovakia (relatively LCOL). When I used to smoke, it was 3.30/pack in Slovakia and 12.50/pack in Ireland. I could legally bring 40 packs back with me, so €368 to be saved - back then that would not only cover flights, but also a couple of nights in a half-decent hotel. (sunken-cost assumed, obviously).

But to compare, for example, an m3pro macbook pro, the difference is €100 - at which point you're really only juggling the difference between 23% and 20% VAT rates.

Outside of europe the gloves come off. Brazil, for example, has famously high import duties - so smuggling the same macbook to Brazil would have a much greater pay-off.

Outside of luxury goods, I suspect the best arbitrage is found in items with high taxes. For which governments are usually not too keen on allowing untaxed imports.