Low postage rate for books. How do they do that?

[moviemem]

I puchased a book for 3.00 and was charged 3.50 for postage in one order. In another order with a different seller, I bought 4 books for 8.00 with free shipping. Both Australian sellers. They were thick books and wouldnt go close to being large letters so I wonder if the sellers just made a mistake or whether there is something I am missing. Other sellers seem to charge very low postage rates for books and they must surely be losing money.

I thought books should go as parcel post.

[transport-posters]

I can't think of how to explain that, unless the seller somehow has access to a company's mailing account or something.  I had a seller send me something like that once.

[lyndal1838]

The seller is probably dropshipping the books from the UK where they have special media rates.

I buy from a UK book seller and get free postage.