Is it still true that you can get the same flight cheaper by booking from another country's version of the site?

It was real, it is still real, and it is much narrower than the folklore version.

The mechanism is point of sale. Airlines file fares per market, and the same physical seat can be sold under different fare rules depending on which country the ticket is issued in. That is a genuine industry structure, not a glitch, and it exists because demand, competition and purchasing power differ by market.

What has changed is where the differences show up. On a simple return between two major cities on a competitive route, the price is now effectively the same everywhere, because those markets are transparent and airlines price them against each other. The differences survive on long, multi-leg, or premium cabin itineraries — precisely the ones almost nobody books.

So your experiment worked correctly. You tested it on the case where it does not apply.

The part the folklore leaves out, which is why your conversions came out level: changing the country on the website is usually not changing the point of sale.

Most airline sites change the display currency and the language, and issue the ticket from wherever you actually are, based on your card and your address. So you see a converted price, you convert it back, and unsurprisingly it matches. You have changed the label on the shelf, not which shop you are in.

Genuine point-of-sale differences generally require the ticket to be issued in that market, which usually means an agent there, a card issued there, or a booking channel that is actually local. That is a lot of friction for a saving that may not exist.

This is why the trick has a reputation for not working: nearly everyone who tries it does the version that cannot work.

For question 3, what does reliably work is much more boring and does not involve pretending to be somewhere:

• Being flexible by a day either side. Consistently the biggest single lever, often by a wide margin, and it takes one search on a flexible-date view.
• Checking the two directions separately as one-ways on carriers that price them independently. Not all do, but where it works the saving is real and there is no trick to it.
• Nearby airports, once you have costed the ground transport honestly, including the time.

And two things worth deliberately not doing, because they are the other half of the folklore: clearing cookies and searching in private windows. Prices moving between searches is overwhelmingly ordinary inventory movement — a fare bucket selling out — not the site recognising you and marking it up. People have tested this repeatedly and the effect does not survive controlled testing.

One practical caution if you ever do find a genuine cross-market difference and decide to use it: check the fare rules before booking, not after.

Tickets issued in a different market can carry different change and refund conditions, and occasionally a requirement to start the journey in that market. The saving is real; so is the possibility that the ticket is useless to you.

Worth knowing rather than a reason not to. It is just that the version of this story people repeat only ever includes the price.