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http://www.ozbargain.com.au/node/38301
and how this is best handled in the future, rather than in the post itself.
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MOD edit - to clarify where the mods are currently on this one, check this post out.
This is a really interesting situation. Personally, when I read "free shipping worldwide", I do assume that it's the same price for everyone, and I do feel a bit wronged to discover that shipping costs are being incorporated into the book prices <i>at a differential rate</i>. Thinking about it, though, if they did not do this, it would probably make them uncompetitive in the US and UK markets. However, it's particularly galling to see that the differences between US/UK and Australian prices are in many cases much more than the postage cost would justify. To me this does seem more like exploiting the high cost of books in Australia - if they can make a profit selling a book at x in the UK and USA, surely they can make a profit selling a book at x + a few dollars shipping to Australia, bearing in mind that shipping would end up being pretty low considering their volume of business.
I suspect there's some complex marketing psychology going on here, and that people often don't make strictly rational decisions. For instance, buying books from Amazon, because there's a per order charge as well as a per item charge, it makes sense to make a bigger order. However, I've never bought anything from Amazon, because when I sit down to work it out, I find the shipping costs prohibitive. With bookdepository, there's no incentive at all to buy more than one item at a time, but I usually do anyway, because I see more books I want while browsing their site, and buy other books I'd been thinking of getting "while I'm thinking of it". This doesn't really make sense, from a financial point of view, but I suspect I'm not the only one who buys more books when not thinking about the shipping charges.
If bookdepository are charging more for books shipped to Australia, I would like the opportunity to get a discount for buying a larger order of books at the same time, but of course their business model doesn't support this, because shipping is "free" ie. included. I am wary of using the hack to buy books at US/UK prices and then get them shipped here, because whatever I think about how they come up with their prices, a sale occurs when an item is offered at a price and accepted at that price, and I do feel the hack is a distortion of this process. However, I think I could still save money on some books by using the hack to ship to a mail consolidation business (e.g. http://www.shipito.com) at the lower US prices. To me, this would be respectful of the actual costs of BD shipping the book, while thumbing my nose at the extra markup they can put on because of the high costs of books in Australia.
Edited to add: my thought about using a 3rd party shipper was based on looking at a couple of high-cost textbooks that I've had my eye on, but upon a 2nd look, I'm not sure if the price difference would make in economical to do this. Can it be just my imagination that the price difference has decreased in the last week???