Australian RRP is not in sync with the RRP of the same/similar title overseas for the most part. That's something important to keep in mind.
Let's say a small bookseller orders books from his supplier; he pays RRP less his discount (30%, or 35%, on average, although with some suppliers or publishers it's even less than that - I know of 15% in a couple of cases) PLUS the delivery/postage charge. He keeps those titles in stock, so he's tied up capital in those titles.
He has considerable costs in running his business, as he has to pay rent, electricity, staff wages, insurance, and so on.
His stock is nicely arranged so customers can browse through the titles, handle them, check things like quality of the print on the page, thickness of the paper, glossiness of the paper, actual colour of the photographs (if relevant), flick through the book to see whether it still "grabs" them (or if it has age-appropriate language if you're buying children's books), etc.
The staff are there at hand: knowledgeable, experienced, able to give first-hand advice and suggestions based on what sort of things the customer likes to read. Really good staff can even guide customers away from titles that aren't really appropriate or good as gauged by the staff from talking with the customer. (Book blurbs can be very misleading.)
I hold to it that this is an entirely different purchasing experience than hopping on to Amazon. I believe there are occasions when it's better to go to a shop than to buy online, and is really helpful to get advice and to gain some idea of the physicality of the goods before you buy. Amazon is fine if you know exactly (and I mean EXACTLY) what you want and don't need it right now and so on... but even then, I've gone to b&m shops in preference to online places such as Amazon for a number of reasons.
I also hold to it that it is rude and offensive for a member of the public to go into a shop with no intention of buying a title from that shop, but simply use the shop as a "choosing ground", scanning barcodes and comparing prices which OF COURSE the shop can't match. If one wants to buy online and get the best price, fine - we all have the right to do that. But then don't go into a shop, using up the staff's time or taking advantage of the fact the shop is still somehow hanging on in this Valley of the Shadow of Retail Death. Do it ALL online; take the risk; make your choice; don't ask for expert advice from staff - that's just rude and selfish.
As far as GST to be imposed on items bought from overseas... no. I don't think that's the solution.
Part of what I see as the problem is that the public look at items on Amazon or Book Depository and honestly think that's the REAL price of the item. "If THEY can sell it for that - and they're obviously making a profit - then I'm not paying the fat cats HERE at their hugely inflated prices" is a general response. But it's false... because there are certainly small businesses who MUST buy from the Australian supplier of a publisher (for distribution rights reasons - and they can be in enormous trouble if they try to bypass the Australian supplier because the publisher/supplier WILL take legal action), who do NOT get an enormous discount, and who have to somehow survive with some rather pathetic margins - not to mention being told how much cheaper Amazon is by the unaware public.
Yes, there are sellers in Australia who are making money hand over fist - they have enormous profit margins, etc., etc. Those are the sellers who can be beaten down on price - JB Hi-Fi, Harvey Norman, Dick Smith, etc. But there are small businesses in various genres who are not making money like that at all.
Have you noticed that apps in the Australian iTunes store are still more expensive than apps in the American iTunes store? Even when we recently had parity with the US dollar?
Hmmm.
I would suggest a good start to the issue of more expensive prices in Australian shops lies with enforcing fair prices for the Australian RRP by the manufacturers/publishers/suppliers. Then Australian small businesses could begin to compete on fairer ground.