An e-book reader, also called an e-book device or e-reader, is a mobile electronic device that is designed primarily for the purpose of reading digital e-books and periodicals.
This is the older model, which has since been replaced with the Kindle paper-white, but although it's refurbished, it's roughly $50 less than the paperwhite 3G.
Whilst trawling the aisles of Officeworks searching for those glorious yellow "clearance" tags, I came across this. As far as I know this is the cheapest so far - but please correct me if I'm wrong.
Bauhn 7" Colour eBook Reader and Media Player
ea $ 49.99 *
Read your favourite novels, play movies, photos or listen to music
4GB built-in memory included and a Micro SD card slot for up to 32GB*
Amazon Kindle Paperwhite (no ads version). $164 at Dick Smith after asking for a OzBargain price (yes, I muttered those exact words, in kind of a subliminal message kind of way).
One of the best eReaders available on the market atm. Slightly better than Paperwhite imho. local stock, smaller, lighter, supports epub among many other formats, micro sd, etc.