Angus and roberston and Borders both have a $5 discount code that can be applied to ebooks
The borders one is BAO-5AU11 and the A&R one is AR-5AUG11.
http://www.borders.com.au/five-plus-ten
http://www.angusrobertson.com.au/five-plus-ten
I purchased The Bricklayer by Noah Boyd for $6.99 pleased with that as it's been on my Kobo wish list for a while($10.99)
There are some ebooks for under $5 so theoritically you could get them for free but none looked appealing to me. I did notice the The Girl with the dragon Tattoo would work out at $1.95 which is good value(I've already read it)
I'm still searching for something to use the second code on.
They also have a deal that if spend $35 now they'll send you a $10 discount code in September but I couldn't see myself doing that as they're usually more expensive than other sources. Not only that but who's going to trust them to pony up the voucher after they reneged on so many gift cards
