tl;dr = Found a watch you like on your native Amazon site? Check overseas Amazon first!
I suspect most people are aware there can often be a significant and worthwhile price difference for many watches, if you look around a bit before purchasing, but this one caught my attention a bit more sharply.
Citizen BM8186-15E - variously called a Chandler or a Garrison, the black PVD coated steel field watch. 37mm x 9.5mm, ~ 50g with strap, day + date complications, Eco-Drive solar quartz movement.
Amazon Australia (home for me) = $379 AUD
Amazon UK = $182 AUD (including shipping; the watch itself was $155 AUD).
So, even with shipping, by switching to the UK version of Amazon, I am paying 48% of the price I'd have paid if I bought it on the Aussie version of Amazon, or if you like to think backwards, the price on the Australian site is 108% _higher_ than that on the UK site: more than double.
Soooo... the watch I was curious about, but don't "need" (I have a very nice Promaster Land titanium PMD56; but I also have small wrists), is now on its way to me from merry olde England. :-)