Quote Originally Posted by DarkHyren View Post
So, basically if it says "Ships from and sold by Amazon AU" the seller is Amazon themselves but if it says "Ships from and sold by Amazon US" the seller could be anyone selling on Amazon US, is that right?
Yes. The US import stock will only ever say that it is coming from Amazon US as international stock, but won't tell you if it is their stock or a 3rd party selling on their site.

In that case how do we figure out exactly which seller the item might come from when we buy the item on the AU site but there are multiple sellers listed on the US site?
What I do is remove the ".au" in the address bar, and remove everything after the product code - eg: /dp/B07JLY4YH4/
That should give you the US listing, and if it has the box on the right side that asks if you want to buy it through Amazon Australia, open that in a new tab/window and see if it is exactly where you started from.
Using that example above for Siege Jetfire, the US listing is from 3rd party sellers, and the Australian page gives you the option of buying from Australian stock at about $148, or American stock (from the 3rd party sellers) for about $146 (and if you are a Prime member and get free shipping on both options, you then decide which one you want to buy if one is significantly less than the other). These two are only $2 apart, so there isn't a big enough saving to get the American stock, because it will take longer, is more likely to get damaged on the way, and will have an Amazon barcode sticker on it somewhere (they put barcode stickers on 3rd party stock for their warehouse computers to use).

Will it always be the cheapest one listed on the US site, or the cheapest one that says "FULFILLMENT BY AMAZON", or something else?
Unknown. If there are more than one seller on the American page, it could well be from any of them.
And the Australian listing prices are annoyingly random, with similar US$ prices ending up being completely different prices when listed on the Amazon Australia site. But the prices of the Australian listings of American stock can often change, but by looking at both AU and US listings at the same time, you can work out which one will be cheaper for you if the Australian price is over-inflated.
Just note, that if you are buying from the American listing, there is no free shipping unless you are also a paid member of Amazon America Prime. AND, the American Amazon site charges GST later when you checkout, so it isn't included in the listed price.
Like that Jetfire toy - if you bought it from the Amazon America listing for their US$88 price tag, you have to then add GST, and shipping AND convert to AU$.... coming to about AU$185.
But that exact same American Jetfire bought through the Australian listing for AU$146, already includes GST and has free shipping if you are an Australian Prime member.
(or the Australian stock for $148, which also already has included GST and free shipping)

When I shop on Amazon, I go to the American site first, and any items that I want, I look on the right to see if they offer it through the Australian site and open up those pages in new tabs to calculate which is the cheaper option... and if either option is under what I am willing to pay.

And since the AU site fails to mention details such as item condition when it's been provided, does that mean some of the USED items from the US site might get sold as NEW on the AU site?
I don't think they sell "used" items as American import stock, because I think they'd need to state it's condition if it isn't new. At least, if the 3rd party seller has the stock listed as new, it should be new if they want to remain in business on Amazon. I haven't had anything arrive that was opened, but the Amazon barcode stickers they put on their 3rd party stock are really annoying, particularly on the more collectable items.